BOOBOOK
JOURNAL OF THE AUSTRALASIAN RAPTOR ASSOCIATION
A special-interest group of BirdLife Australia
Volume 31 Number 2
July 2013
ARA CONTACTS
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NT
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The aims of the Association are the study, conservation and management of diurnal
and nocturnal raptors of the Australasian Faunal Region.
Boobook 31(2) July 2013
25
FROM THE PRESIDENT
Greetings, fellow raptorphiles!
The ARA national conference is being held at the Adelaide Zoo on 10–11 August 2013. Our regional
representative (Ian Falkenberg), in conjunction with Birds SA, has organised a line-up of speakers that
promises to inform, challenge and entertain. I encourage all ARA members to get along to it. All members,
students of ornithology and other raptorphiles are welcome and invited to attend. These conferences only
happen once in a ‘blue moon’, so I strongly suggest that if you have even the slightest interest in raptors then
come to Adelaide in August. These conferences are a rare opportunity to meet and learn from the ‘best in the
game’ (or so we like to think we are), but also to enjoy some of the ripping yarns shared amongst raptor
experts about the ‘one that got away’.
It is this human element, after all, that can have the greatest influence on how we engage with raptor
conservation projects. Although much of the field work maybe solitary, and it often is, having contacts in
‘the field’ whom you can call is helpful when obstacles occur. Or, more hopefully, when you wish to
interpret some new or novel raptor behaviour, then someone you have heard present at or met at an ARA
conference may be just the person to call. In the early days of my raptor studies it was just such people who
offered encouragement or support, and helpful advice that allowed me not to repeat their mistakes. I’m
certain that in the early days I went out and created my own original mistakes. At least, I like to think that
some of them were original.
In this sense, attending a conference is not so much about the world-beating original science you will hear of
or the inspirational tall stories people may tell. It’s not only about hearing of new studies on species you
have never seen or those you wish you had. Attendance at a conference is an opportunity to connect with the
people who can help you in developing your own study. The bonding experience of attending a conference
on a specialist subject, such as raptor conservation, is about making connections with others. For those of us
who have been working in this field for some years now, it is also an opportunity to re-energise our approach
to our own raptor projects. The ARA conference does not have multiple sessions with speakers presenting
concurrently in several rooms or venues, so it is less of a task to attend your favourite presentations. More
time can be spent between sessions meeting people and catching up with those you do know.
When we gather in Adelaide in August I hope that I, and the other speakers along with the science we
present, we will share some of these experiences with our audience. The fascination with raptors among
birdos and the general public is near universal, and yet it is a small group of humanity that ever actually gets
close to these magnificent birds. I often have to remind myself that not everybody abseils down cliff faces to
band raptors. So I will share with you some of the adventures I have had in a raptorial life.
I look forward to meeting you in Adelaide!
Raptorially yours,
Victor Hurley
For a conference update, see p. 42 of this issue.
Journal of the Australasian Raptor Association
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Boobook 31(2) July 2013
EDITORIAL
In this issue we have several controversial or provocative articles that challenge some common beliefs about
Aussie raptors, or that invite a response. And here’s some more food for thought from the anonymous
referee who commented on a draft paper on Peregrine Falcon parenting (p. 30): ‘There are another halfdozen papers/ideas commonly cited that are [more deserving of critical review]; for example, Olsen &
Cockburn (1991) where they claim sex-ratio differences in nestlings from Peregrine nestlings that were
guessed at mostly by amateur banders, stats are wrong, but it is commonly cited by people who cannot
replicate it then say Australian Peregrines must be different! There are many more. If you look at what
characterises Australian raptor research more than anywhere else it is the use of hearsay as evidence.
Australian raptor papers are full of this, and when I question these bits of hearsay, editors over-rule me.’
Perhaps it’s time for Australian raptor students to look critically at accepted dogma.
In this issue we also have reports of a new owl species in the region; an obscurely published study on Grey
Falcon calls; issues relating to eagle nests in Tasmania; a variety of field notes (mostly on our special
endemics – always good to see); a review of the new BirdLife raptor field guide; literature listings; abstracts
from the BirdLife raptor and owl seminar; and some highly relevant international news. The matter of eagle
nests in Tasmania raises the issue of animal ethics committees hindering important work on threatened or
other native species – work that is to the benefit of those species and their populations. It seems that
(sometimes unwarranted) animal-welfare concerns, or animal-rights attitudes and interference, can override
critical conservation-biology work on species threatened with extinction! Of course, AECs are needed to
ensure ethical practices and safeguard the welfare of animals.
The next issue of Boobook, planned for late in the year, will largely feature the ARA conference abstracts.
However, I will still need a variety of other material to help carry it (e.g. responses to ‘Raptor file’ items;
field notes). We haven’t had reports lately from most Area Reps, but it would be good to know what the
Reps and other members are up to in, e.g., NT, Qld or NSW with respect to raptor studies or issues. I would
also like a conference delegate to provide a report on the ARA conference, soon after the event.
Recent analyses (e.g. atlas reporting-rate trends) show declines in many raptor and other Australian bird
species over the last few years or decades, with additional species listed as, or considered, threatened (e.g.,
watch out for the NSW Bird Atlas vol. 1 – non-passerines, currently in prep.). This situation is symptomatic
of the current upsurge of environmental assaults, aided and abetted by government abdication of
responsibility, downsizing or financial strangling of departmental and non-government watchdogs,
cancelling of biodiversity research, fast-tracking of big developments, inadequate impact assessment, gutting
of environmental legislation, and so forth. We seem set for an environmental dark age, in which our record
on birds will likely catch up with our appalling (and globally shameful) record on native mammals. For
instance, the last two issues of Nature New South Wales (journal of the NSW National Parks Association)
detail the current litany of government-sanctioned attacks on national parks in most Australian states
(hunting, grazing, logging, mineral prospecting, 4WD-driving, quad-bike tours, horse-riding, mountainbiking, commercial resort development, erosion of wilderness values, etc., along with gutting of park budgets
and staffing) – these in the very areas in which nature conservation is supposed to be the top priority.
Clearly, the people clamouring for exploitative uses of conservation reserves have no idea of the primary
intent or purpose of national parks. Also, those clamouring for grazing in national parks (as alleged ‘drought
relief’) also seem to have no concept of reference areas as benchmarks for their own (mis?)management,
livestock carrying capacity, or the likelihood that their own land is chronically overstocked, etc. As a
colleague recently said, ‘National parks don’t eat grass’! See the last issue of Nature NSW for some mythbusting about wildfire and prescribed fire, hunting in national parks, and a commentary on private native
forestry and its effect on fauna (e.g. a firewood merchant doing the threatened-species assessment in his
forest!). This is where we’re headed (and after the next Federal election? – the mind boggles).
Stephen Debus
Journal of the Australasian Raptor Association
Boobook 31(2) July 2013
27
REPORTS AND NEWS
BirdLife Australia EagleCAM at Sydney Olympic Park
Features for 2013:
• 24/7 viewing – the infrared (IR) light is working this year, giving great night views of the nest.
• New camera position – we have moved the fixed high-definition (HD) camera to a position 5 m from
the nest, showing us into the nest bowl from behind the nest.
• Two-camera view – the pan, tilt, zoom (PTZ) cam is back in the same position as last year, so we
now have two opposing camera views.
• New Internet connection – we will have a new Internet connection soon that will mean we can
stream two cameras in HD.
Sea-EagleCAM live stream on Ustream has had over 2 million views; congratulations to all those people
who have assisted in the project.
After last year’s eaglets (S3 & S4) fledged and left the area, both adult Sea-Eagles have been visiting the nest
about once a week but only staying for a few minutes. On 13 April the male Sea-Eagle delivered the first
stick to the nest, marking the start of the 2013 nesting season. Both adults dedicated themselves to 3 weeks
of intense nest renovation, bringing lots of sticks. Then suddenly they stopped, only visiting once per day.
We took this as an opportunity to remove the cameras for maintenance and to reconfigure them for the new
camera location. We had the cameras down for about 9 days before reinstalling the PTZ camera in the same
location as last year, looking south, and the fixed zoom-only camera about 5 m from the nest, looking north.
This camera has the IR light mounted on top.
The adult Sea-Eagles had about 3 weeks’ rest in renovation, but are back in earnest and have raised the nest
rim by about 30 cm. The first fish was delivered to the nest by the male on 27 May; the female did not pick
it up until the next day. There have been a few more fish since then, the male showing that he can provide
for the female and chicks. They have started to bring in leaves to line the nest in the last few days, so there is
lots of action on the nest.
EagleCAM is a BirdLife Australia Southern NSW research project. They have been studying this pair of
eagles using CCTV since 2009. Our website at www.sea-eaglecam.org has a wealth of information about
White-bellied Sea-Eagles. There are links to most study papers about Sea-Eagles, and lots of info about this
pair of Sea-Eagles in particular. There is also the live videos stream showing both of the cameras, along with
the chat room, all on the same page: www.sea-eaglecam.org/video.html. The live stream is still running
on www.ustream.tv/seaeagles; the second camera can be viewed on www.ustream.tv/channel/seaeagle-watch1. For up-to-date information, videos and news go to www.birdlife.org.au/visit-us/discoverycentre/eagle-cam. Keep up to date on www.facebook.com/sea.eaglecam. Join the forum www.seaeaglecam.org.
EagleCAM e-newsletter no. 6, June 2013 (per Geoff Hutchinson)
New owl species for Wallacea
A morphological and genetic study of masked-owl taxa in Wallacea and Melanesia has concluded that the
form long suspected on Seram as the Lesser Masked Owl Tyto sororcula (and inferred to be T.s. cayellii
which occurs on neighbouring Buru) is in fact a separate species, the Seram Masked Owl Tyto almae.
Furthermore, this study also concludes that the Lesser Masked Owl and the Manus Masked Owl T. manusi
are probably only subspecies of the Australian Masked Owl T. novaehollandiae. The Seram Masked Owl
clusters with the Golden Masked Owl T. aurantia, of New Britain, at the base of the masked-owl genetic
tree. See:
Jønsson, K.A., Poulsen, M.K., Haryoko, T., Reeve, A.H. & Fabre, P.-H. (2013). A new species of maskedowl (Aves: Strigiformes: Tytonidae) from Seram, Indonesia. Zootaxa 3651: 51–61.
Journal of the Australasian Raptor Association
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Boobook 31(2) July 2013
Victorian Area Rep’s report for 2013
Greetings to all. The year from May 2012 to June 2013 has been a busy year for raptor sightings across
Victoria, particularly for species such as Black Kites, and the normally less common Black Falcons and
Spotted Harriers. These three species, in particular, seem to have benefitted from considerable breeding
success inland, and the increase in reported sightings perhaps reflects the increased number of individuals
dispersing from those inland breeding sites as the inland dries out. Of particular note are the records of
sightings of Black Falcons associating with Black Kites (which the former species regularly harasses and
steals prey from). At the Western Treatment Plant (WTP) in September, two Black Falcons were seen flying
with seven Black Kites.
Black Falcons were seen right across the state – Mooloort Plains (with one pair successfully breeding there
last season), Mill Park Lakes, Bacchus Marsh, Braeside Park, Winton Wetlands, Swan Bay, Yarra Valley,
Little River, Altona, WTP, Point Henry, Exford and Westgate Park, Pyramid Hill, Barwon Heads, Inverleigh
and others. Of particular interest is the number of sightings close to the WTP and the Geelong area
(confirming the observation that this species spends the spring/summer/autumn months close to the coast
there).
Black Kite irruptions were notable for the numbers of individuals sighted. At Dookie in April, 120 were
seen, and at least 40 at Joyce’s Creek were seen in May 2013 (a lone Black Falcon with them). Sightings of
Black Kites ranged across Victoria from the above locations, and included Fawkner, Tylden, Plenty Gorge
and Homerton, to name a few.
Spotted Harriers bred successfully in central Victoria, and they were seen in places as diverse as Brunswick
in the city’s north to Exford, Tyabb, Sunbury, Clyde, Cockatoo, Maffra, Barwon Heads, the WTP at
Werribee, Koo-Wee-Rup, and other sites.
The Square-tailed Kites I reported from central Victoria last year appeared not to breed this past year, but
sources inform me that there are suspected to be two breeding pairs locally.
Many observations were of species in the suburbs and close to the CBD. Some of the observations of note
were: a juvenile Little Eagle seen at Pipemakers Park along the Maribyrnong River, and a second sighting at
Westgate Park; and a lone Brown Falcon catching what appeared to be moths on the West Gate Bridge
western support pylon (which hosts the giant Australian flag atop!)
David Whelan
Eagle nest issues in Tasmania
The only manipulations of eagle nests, by human managers, in Tasmania known to me were:
1. Installing a Wedge-tailed Eagle nest near another that was disturbed, and it was used some years later in
an exceptional breeding season when most eagles bred (who knows which particular Wedgies used it);
2. (Without authorisation) installing a White-bellied Sea-Eagle nest at Woolnorth [i.e. near the windfarm], to
try to encourage a pair to move (which it didn’t).
Our policy of treating Sea-Eagles as we do Wedgies saves some dramas (this habit developed in forestry
management because the two species often used the same nest in different years). That aspect appears to be
worsening, as both species increasingly compete over the same nest patches. I intended to put a camera near
a Sea-Eagle nest, but it will have to go through an animal ethics committee, so that’s stalled for this year.
Nick Mooney
…another case of an AEC (or its requirements) hindering good, expert ecology/conservation work? (Ed.)
Journal of the Australasian Raptor Association
Boobook 31(2) July 2013
29
Grey Falcon vocalisation study
At the BirdLife raptor seminar last March I fortuitously found out about a recently published paper, with
sonograms, describing the calls of the Grey Falcon, deriving from sound-recordings obtained by two
enthusiasts. It is in a rather obscure publication (AudioWings, journal of the Australian Wildlife Sound
Recording Group), and appeared concurrently with another Grey Falcon study (Watson 2011, Aust. Field
Ornithology 28: 167–179) that could usefully have cited and discussed it, had we known. See:
Baylis, T. & van Gessel, F. (2011). Observations and sonograms of the calls of Grey Falcon Falco
hypoleucos. AudioWings 14(2): 8–9.
Having listened to the recordings on the AWSRG CD, I would say that the calls (as labelled in the paper) are
as follows. Figure 1, ‘Greeting call’, is a fast cackle, softer and clearer than the Peregrine’s. Figure 2,
‘Whining call’, is a juvenile begging call (possibly a male). Figure 3, ‘Whining call (variation)’ is another
juvenile begging call (possibly a female). Figure 4, ‘Cackling call’, is a slower (than Fig. 1), ‘complaining’
cackle, not staccato. In some of the calls or phrases there is a hint of Peregrine quality. The calls were from
two families of Grey Falcons that had new fledgling(s), and the paper also describes some interesting
behaviour in the early post-fledging period. I think the information could usefully have been written up
properly as a paper in a mainstream ornithological journal like AFO. (Ed.)
Accipiter genetic study
A recent paper on the intrageneric relationships within Accipiter (molecular phylogeny: Breman et al. 2013)
mostly considered African and Eurasian goshawks and sparrowhawks. Of the species occurring in or near
our region, the authors conclude that the Besra A. virgatus and Japanese Sparrowhawk A. gularis are
genetically very close, but that the latter specimens (DNA sources) were collected outside the known range
of gularis and may have been misidentified virgatus! They also conclude that their Brown Goshawk A.
fasciatus sample belongs genetically with the virgatus-gularis clade, but that its DNA came from a juvenile
skull which may have been a Collared Sparrowhawk A. cirrocephalus; and furthermore, that this skull DNA
is very similar to cirrocephalus DNA, and so their ‘Brown Goshawk’ was probably a misidentified
Sparrowhawk! These non-conclusions just confuse the issue, when they could have simply said that they
couldn’t resolve the relationships of A. gularis or fasciatus on the grounds of doubtful provenance and/or
identity of the specimens concerned. See:
Breman, F.C., Jordaens, K., Sonet, G., Nagy, Z.T., Van Houdt, J. & Louette, M. (2013). DNA barcoding and
evolutionary relationships in Accipiter Brisson, 1760 (Aves, Falconiformes: Accipitridae) with a focus
on African and Eurasian representatives. J. Ornithology 154: 265–287.
We’ll just have to wait for someone to do the Asian/Australasian Accipiter species, in the context of the
whole genus, properly next time. (Ed.)
Black Falcon listing in NSW
The Black Falcon has received a final determination (on 12 April 2013) to list it as Vulnerable in NSW under
the Threatened Species Conservation Act 1995. See:
http://www.environment.nsw.gov.au/resources/threatenedspecies/BlackFalcVSFD.pdf
Journal of the Australasian Raptor Association
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Boobook 31(2) July 2013
RAPTOR FILE
Do Australian Peregrine Falcons parent differently?
I was privy to the following comments, by a Peregrine expert, on the paper by P. Olsen et al. (1998, Emu 98:
297–304) on sex roles in breeding Australian Peregrines (Ed.):
Overseas people are finding that hunting by breeding female Peregrines is important during the nestling
period, and cannot understand why Australian Peregrines are allegedly different. [This person says they’re
in fact not different from overseas Peregrines in this respect –Ed.]. No prey analysis (I have a lot of
unpublished data) has found Australian Peregrines taking House Sparrows, and there have been thousands of
prey items analysed, yet Olsen and/or her collaborators (cited in her 1995 book and in the 1998 paper)
watched, from some distance with binoculars, Peregrines regularly catch or bring in [supposed] House
Sparrows. What does this tell you? My guess is that they misidentified plucked juvenile Common Starlings
and perhaps other small birds as House Sparrows, and also could have mis-sexed the Peregrines at times.
Sexing [single] Peregrines can, as you know, be difficult in the field.*
*[In agricultural habitats in Victoria, Mark Mackinnon (see thesis listing, Boobook 31, p. 23) found 18
House Sparrow remains among 1067 prey items (orts and pellets), or 1.6% by no. and 0.3% biomass; not a
large dietary component –Ed.]
Essentially I think that female Peregrines operate as suggested by J. Olsen & Stevenson (1996) and J. Olsen
& Tucker (2003), with flexibility depending on male hunting rates and success, perceived risk of predators
(including humans), and weather. None of the references that Olsen et al. (1998) claimed to support their
argument actually did so when I checked them. Holthuijzen (1990) essentially supports my position, a
different view from the rigidity of male-female roles portrayed by Olsen et al. (1998). Also, following is a
copy of my referee’s report (on a recently submitted paper) that incorporated a critique of Olsen et al.
(1998), because the author of the new paper had cited that earlier paper.
Here in a nutshell is the problem with Olsen et al. (1998) as I see it. It seems that the issue is simple:
(1) J. Olsen & Stevenson (1996) and J. Olsen & Tucker (2003) argue flexibility around sex roles, that
male/female hunting, incubation, defence etc. can vary with prey, brood size, individual raptors, perceived
risk of predation and inclement weather.
(2) In contrast, Olsen et al. (1998) argue that there is no such flexibility, and that male/female roles are fixed.
People need to read Olsen & Stevenson first, then argue. Olsen et al. (1998) say the opposite to Olsen &
Stevenson.
And here are my comments, to the author(s) via a journal editor, as a referee on the above-mentioned draft
paper:
‘Olsen et al. (1998) paper: this paper, cited in your draft, generates some problems because their findings
contradict yours, (i) they did not find increased prey size with increased brood size, (ii) they did not find that
females with larger broods provisioned more than females with small broods, and (iii) they argue that the
literature on provisioning in raptors in relation to brood size shows that only males respond to large broods,
not females – the opposite to what you show. My suggestion is that you look carefully at the methodology
and assumptions in the 1998 paper, and read the references they cite in support of their findings to see if
these references say what Olsen et al. claim they say. I can only start this process for you:
‘(i) Olsen et al. (1998) did not address prey size vs brood size. They may have found it, but did not report it.
Some studies have found that raptors do bring larger prey to larger broods, and rarely bring large prey to
small broods. In Peregrines: Palmer et al. (2004), Olsen & Tucker (2003), Olsen & Stevenson (1996), and
your study. In Hen Harriers (assuming that a male with two or three females has more young than a male
with one female): Redpath et al. (2006).
‘(ii) Several papers or books argue that female raptors do adjust their provisioning effort to their mates’
provisioning ability; see Newton (1979), Tolonen & Korpimäki (1994), Rohner & Smith (1996). Also,
Olsen & Tucker (2003), Olsen & Stevenson (1996) and Redpath et al. (2006) argued that females responded
Journal of the Australasian Raptor Association
Boobook 31(2) July 2013
31
to food shortage, linked to poor male provisioning or enlarged brood size, by providing larger prey. Olsen &
Tucker (2003) argued that female raptors may perceive human observers as predators, especially if the
observers are regularly disturbing the nest by measuring nestlings, and this may alter normal female hunting
behaviour and induce them to ‘watch the watchers’, that is, guard the nestlings instead of hunting. This
behaviour could partly explain the unusual loss of large nestlings in the Olsen et al. (1998) study.
‘(iii) Olsen et al. (1998) draw the main support for their position that females do not compensate for male
provisioning from “Male provisioning rate has been shown to be positively correlated with brood size in
Peregrine Falcons (Nelson 1988) and other raptors such as Prairie Falcons F. mexicanus (Holthuijzen 1990),
Eurasian Kestrels F. tinnunculus (Palokangas et al. 1994; Tolonen & Korpimäki 1994) and Northern
Harriers Circus cyaneus (Simmons 1989)”.
‘Nelson (1988) did not measure provisioning. He examined mortality rate and brood size in Peregrines, and
found that large brood size was significantly related to higher mortality in parent females, but not quite
significantly related to mortality in parent males.
‘Holthuijzen (1990) did not cover this aspect. In correspondence he said: “…concerning prey delivery rates
in Prairie Falcons. Your question was whether prey deliveries increase in both males and females with brood
size. The long answer is as follows. There is considerable variation in prey delivery rates among the Prairie
Falcon pairs we studied... That is the reason that I combined prey deliveries per pair to investigate
relationships between brood size and prey deliveries. Such a clean relationship is not found when prey
delivery rates for males and females are regressed on brood size separately. However, both male and female
do increase their prey delivery rates during brood rearing, but tend to compensate each other. For example,
in abundant Paiute Ground Squirrel years, males were able to provide sufficient prey for their young, and
females were content to guard the nest site. However, some females were excellent providers and males
guarded the nest sites.”
‘Palokangas et al. (1994) did not find that ‘bright’ (successful) males provided more prey items than duller
males, and they did not look at foraging time of females after the nestlings were 2 weeks old, at which time
one would expect females to increase their foraging.
‘Tolonen & Korpimäki (1994) looked at “parental effort” in males and females differently: hunting time in
males, prey deliveries in females. One suggestion they make is that females might adjust their foraging
efforts to the food-provisioning ability of their mates.
‘Simmons (1989) did suggest that male provisioning in polygynous harriers was related to brood size, at least
in the early stages. However, Redpath et al. (2006) showed that males and females in polygynous pairs
adjusted to larger broods by delivering larger prey.
‘In short, I suspect that the literature supports your position [on female hunting], but you may need to look
further on this subject. Results of the Olsen et al. (1998) paper have never been replicated.’
Olsen, J. & Stevenson, E. (1996). Female Peregrine Falcon Falco peregrinus replaces an incubating female and raises
her young. Australian Bird Watcher 16: 205–210.
Olsen, J. & Tucker, A.D. (2003). A brood-size manipulation experiment with Peregrine Falcons, Falco peregrinus,
near Canberra. Emu 103: 127–132.
Olsen, P., Doyle, V. & Boulet, M. (1998). Variation in male provisioning in relation to brood size of Peregrine Falcons
Falco peregrinus. Emu 98: 297–304.
…this commentary is published anonymously, in case the referee requested anonymity to the journal editor
concerned. (Ed.)
Journal of the Australasian Raptor Association
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Boobook 31(2) July 2013
Sooty Owl taxonomy
As part of an online debate on the relationships between the Sooty Owl taxa, Lloyd Nielsen offered the
following, which is reprinted in Birds Qld Newsletter 14(1), February 2013 (p. 15) and here ‘recycled’.
Presumably, it was a rejoinder to the online (Bird Forum) exchange reprinted in Boobook 28: 7 (2010).
It is to be hoped that the [Southern] Boobook studies under way will take into account other factors along
with genetics. I’m afraid I have no confidence in some of the findings of geneticists where determination of
species is based on DNA evidence alone. While some of these decisions are OK and useful, a few are
ridiculous. The classic example of this has to be the very conservative lumping of the Lesser Sooty Owl
with the other two races of Greater Sooty Owl by Norman et al. (on DNA evidence alone), completely
disregarding other factors which by themselves strongly point to the fact that the Lesser Sooty has already
evolved into a very distinct species. Unfortunately, while König later regarded the Lesser Sooty as a distinct
species in his study [based on Wink’s DNA results], the IOC opted to follow Norman et al.
The lumping was apparently done on the grounds that the three Sooty Owl taxa have similar/identical DNA.
But so apparently do birds (species-pairs) such as Grey and Chestnut Teal, White-browed and Masked
Woodswallows, the two black-cockatoos in south-west WA. Where is the consistency? [And how come the
two Sooty Owl DNA studies reached opposite conclusions? –Ed.]
There are several important differences between these two Australian owls – e.g. the larger Sooty
(tenebricosa) has a home range of about 350–800 ha, sometimes as much as 3000 ha, with nests far apart and
well out of earshot of each other. Conversely, the Lesser Sooty (multipunctata) comes close to being a
communal breeder. Territories can be as small as (and often are) 50 ha or less in extent with nests as close as
400 metres, sometimes less, and well within earshot of each other*. Of all the other territorial Australian
owls, only the Southern Boobook approaches this sort of breeding density. There are other differences.
*Hardly ‘communal breeding’ at those inter-nest distances and densities; even eagles and Powerful Owls
can breed that close to a neighbouring pair where prey is very abundant; it’s all about prey densities, in this
case in the tropical versus temperate zones. (Ed.).
In the early 1970s, the late David Fleay attempted to interbreed a male Lesser Sooty with a female southern
Sooty in captivity. After two torrid years of reluctant and fiery courtship, the female finally nested and
hatched two young, whereupon she immediately set upon the male, killed him and fed him to the nestlings!
I think we have to move past declaring species or subspecies on genetics alone, especially in the more
complicated cases. While it is a great tool, surely it should be corroborated by other lines of evidence,
balanced by good field research, emphasis on plumage, behaviour, territory, song, calls and many other
things. Surely field work still has a critical role. Unfortunately, one gets the feeling in some instances that
the science seems to overshadow a good dose of common sense!
Lloyd Nielsen
More on Tasmanian Boobook migration
Thanks to Nick Mooney for further comments on the likelihood or not of Tasmanian Boobooks migrating
across Bass Strait (Boobook 31(1), March 2013, p. 6). Still, there is little hard evidence for this migration,
versus evidence for occasional dispersal, or vagrants reaching the mainland. Boobooks can be road
casualties or caught in wire fences or strike windows, especially after the breeding season when young are
dispersing, and one way to gather evidence around this question is to network all rehabilitation centres in
Tasmania and Victoria to ask for a tally of Ninox novaeseelandiae leucopsis that come in. These could be
photographed. Secondly, birdwatchers in Tasmania and Victoria could be networked and participants asked
to photograph any road-killed, otherwise dead or injured Boobooks they find, publish photos online, and get
an estimate of the numbers of N. n. leucopsis seen in winter, April to September, in Tasmania versus
Victoria. Also, to compare figures for vagrant or dispersing species, it would be helpful to compare the
Journal of the Australasian Raptor Association
Boobook 31(2) July 2013
33
number of N. n. leucopsis reaching the mainland with the number of Barn Owls Tyto javanica reaching
Tasmania (assuming that Barn Owls are trans-Bass Strait vagrants, not migrants).
New Zealand Moreporks N. n. novaeseelandiae are similar to N. n. leucopsis and live in similar, though
harsher, environments than Tasmania. Moira Pryde has radio-tagged 62 individuals in temperate forest
around Eglinton in Fiordland, in the south-west of the South Island. So far, the greatest movement recorded
has been 16 km. The Moreporks stay through winter, even in the snow. At least some Boobooks also stay
on top of the bitterly cold Brindabella Ranges in the ACT during winter; they respond when you play calls of
Powerful Owls N. strenua, and our limited radio-tracking data for Canberra adults show that adults don’t
leave during winter.
Overall, in the claims from Nick’s informants (last Boobook), no dates are given, no notes, no photos, so it is
hearsay. The islands he mentions (Albatross, Hunter) are in a chain close to the mainland, only 10- or 20-km
flights, easy for a Boobook, and well within the range that we know Canberra and NZ juveniles, from
sedentary populations, disperse. There still is no hard evidence for migration of Boobooks from Tasmania.
Jerry Olsen
Was there clutch-size depletion in Wedge-tailed Eagles after myxomatosis was introduced?
Evidence for eagle/rabbit interactions in Australia are drawn mainly from analogies with overseas systems.
Several species of small rodent (voles and lemmings) undergo regular population fluctuations of 4–5 year
cycles in North America and Fennoscandia, and in Northern Canada Snowshoe Hares Lepus americanus
show similar cyclic patterns in about 10-year cycles. Raptors in the Northern Hemisphere respond to
increasing or decreasing lagomorph and rodent numbers in at least two ways: numerical response, raptors
increase or decrease in number, or breeding response, raptors produce more or fewer eggs and/or young.
Though Australian raptors did not evolve with hares, voles, or lemmings, people assume that Australian
raptors cycle with introduced European Rabbits Oryctolagus cuniculus in the same way that Northern
Hemisphere raptors cycle with native rodents and lagomorphs, even though rabbits in Australia are different
from hares, in a different genus with different life histories. Regardless, Australian researchers use these
Northern Hemisphere studies as analogue templates, and assume that drought in Australia, and/or diseases
such as myxomatosis should act on rabbit numbers, and on Australian raptors, in the same way that cycling
hares act on raptors in the Northern Hemisphere. Furthermore, many researchers predicted that the Rabbit
Haemorrhagic Calicivirus Disease (RHD) would act in the same way as myxomatosis and reduce rabbit
numbers (which it generally did), then reduce Wedge-tailed Eagle Aquila audax numbers and breeding
success (Newsome et al. 1997; Sandell & Start 1999). However, evidence for these declines in eagle
numbers or breeding success did not eventuate (Edwards et al. 2002a,b; Steele & Baker-Gabb 2009). How
solid was the original evidence that Wedge-tailed Eagle numbers and breeding were affected after
myxomatosis was introduced in the 1950s?
Baker-Gabb (1984) made the first comparative dietary study of Australian raptors (12 species). For the
seven rabbit-specialists, the Brown Falcon Falco berigora, Brown Goshawk Accipiter fasciatus, Black Kite
Milvus migrans and Little Eagle Hieraaetus morphnoides had biomass of rabbit above 85% in their diets,
and Wedge-tailed Eagles, Spotted Harriers Circus assimilis and Whistling Kites Haliastur sphenurus had
biomass of rabbit less than 85%. Of the rabbit-specialists, the Wedge-tailed Eagle had the least rabbit by
biomass, 69.6% (see Table 1).
These comparative findings of percent biomass in raptor diets were broadly supported by later studies
conducted south of 25° latitude in Australia where rabbits were most common. Aumann (1988) studied
Brown Goshawks in Victoria and found that they took 52.1% rabbits by biomass; McDonald et al. (2003)
studied Brown Falcons in Victoria and found that they took 61.8% rabbits by biomass, Olsen et al. (2010)
compared the diets of Wedge-tailed Eagles and Little Eagles breeding near Canberra and found that Little
Eagles took 52.4% rabbits by biomass, compared with 12.7% for Wedge-tailed Eagles, a lower overall
proportion of rabbit than Baker-Gabb found, but reflecting the difference between the two eagles – Little
Eagles take proportionally more rabbits than do Wedge-tailed Eagles.
Journal of the Australasian Raptor Association
34
Boobook 31(2) July 2013
Table 1. (i) Percent rabbit biomass in diet of main rabbit predators near Mildura Victoria (after Baker-Gabb 1984) and
(ii) decrease in clutch post-1953 (after Olsen & Marples 1992). Percent biomass of rabbit in the diet above 85% and
significant clutch-size reduction are bold italicized.
(i) % rabbit
in biomass
(ii) clutch
size decrease
post-1953
Wedgetailed
Eagle
69.6
Spotted
Harrier
Whistling
Kite
Brown
Falcon
Brown
Goshawk
Black
Kite
Little
Eagle
80.0
83.1
87.0
89.8
91.3
92.1
Yes
No
Yes
No
Yes
No
No
Olsen & Marples (1992) studied the clutch sizes of 24 diurnal Australian raptor species from eggs collected
mainly by amateurs before 1954 and after 1953 when myxomatosis reduced rabbit numbers, mainly below
25° latitude where rabbits were most abundant. They found a mean decrease in clutch size in only three of
24 species – Brown Goshawks, Whistling Kites and Wedge-tailed Eagles – and this has fed the existing
narrative that rabbit numbers strongly affect the breeding numbers and success of Wedge-tailed Eagles.
Aspects of this study could form questions for further study. Firstly, the authors measured clutch sizes after
1953 but did not state for how long after 1953, or why they did not show clutch-size changes year by year, or
decade by decade. Secondly, no researchers have replicated this study or looked for other factors occurring
after 1953 that could influence clutch sizes: factors such as weather, different egg collectors, laws against
egg collecting, areas where myxomatosis hit versus areas where it did not hit, numbers of alternative main
prey such as kangaroos, and reduced persecution of Wedge-tailed Eagles after 1953. Leopold & Wolfe
(1970) said that the number of Wedge-tailed Eagles killed each year in Australia [then] could have exceeded
30 000. The bounty on Wedge-tailed Eagles was lifted in Western Australia around 1968 and, until 1968,
13 056 scalps per year were handed in. The species was first protected in South Australia in 1972 (South
Australian National Parks and Wildlife Act 1972), in New South Wales in 1974 (New South Wales National
Parks and Wildlife Act 1974), and in Victoria in 1975 (Victorian Wildlife Act 1975). So there were many
more eagles competing for limited food after the 1970s than in the 1950s and 1960s, when persecution was
high. Could dividing the samples pre- and post-1975 instead of pre- and post-1953 better correlate with
differences in clutch sizes? Thirdly, given the large numbers of clutches involved in these samples,
statistical artefacts could occur, and these could be corrected. Fourthly, if you look at studies such as BakerGabb (1984) who studied prey taken by breeding raptors in western Victoria (Table 1 above), the species that
took the most rabbit, by biomass, were the Black Kite, Little Eagle, Brown Goshawk and Brown Falcon, but
Olsen & Marples (1992) found no decline in clutch size after 1953 for any but the Brown Goshawk. In their
sample, the clutch size of Black Kites actually increased.
In short, amongst the seven rabbit predators studied by Baker-Gabb, the findings of clutch depletions in three
species in Olsen & Marples seem almost random (Table 1). The authors explain the lack of clutch-size
decline in Black Kites on that species’ tendency to forage on ‘offal and human waste’, but this is not what
Baker-Gabb (1983) showed. Olsen & Marples found no decline in clutch sizes for any falcon species. They
argued that changes in clutch sizes in falcons are much less marked than those of accipitrid species with a
similar diet, citing Porter & Weimeyer (1972) and Cramp & Simmons (1979). However, Porter & Weimeyer
say nothing about differences between clutch-size alteration in Accipitridae versus falcons, and Cramp &
Simmons say, about clutch-size changes in falcons versus Accipitridae, ‘trends in relation to diet much as in
Accipitridae, but annual fluctuations in rodent-eating Falco much less marked than in rodent-eating harriers
Circus and buzzards Buteo’ (p. 281). Cramp & Simmons did not compare rabbit-eating falcons similar to
Brown Falcons with eagles or goshawks. Instead, they were suggesting that harrier clutch sizes should vary
with changes in rodent numbers. Both Australian harrier species, the Spotted and Swamp Harrier Circus
approximans, are major rabbit predators (Baker-Gabb 1982, 1984), but Olsen & Marples found no change in
clutch size pre- and post-1953 for either harrier species, contra Cramp & Simmons.
In contrast to the claims that changes in rabbit numbers affect Wedge-tailed Eagle clutch sizes in museum
collections, no field studies have found clutch reductions related to post-myxomatosis (1953) eggs (Table 2).
Ridpath & Brooker said that the only clutches of three eggs they found (two clutches) were in years of high
rabbit numbers, and this claim was repeated by Olsen & Marples (1992) and elsewhere; however, Ridpath &
Brooker were not measuring rabbit numbers in the years when the two clutches of three were found.
Journal of the Australasian Raptor Association
Boobook 31(2) July 2013
35
Table 2. Post-1953 clutch sizes for Wedge-tailed Eagles.
Source
Olsen & Marples (1992)
Leopold & Wolf (1970)
Ridpath & Brooker (1986)
Parker et al. (2007)
Clutch size
1.84
No. of clutches
(184)
1.97
2.04
2.00
(206)
(96)
(13)
The claim that Wedge-tailed Eagle clutch size declined after 1953 could be a myth, though one that received
currency and unquestioning support. The Olsen & Marples study cannot be replicated exactly because we do
not know where the clutches came from, or how many years after 1953 the eggs were collected and included
in their sample. Some of these egg collections are now traded, broken up, or disappeared. A replication of
sorts could be done with existing eggs in museum collections – go back to original egg-collection cards, recheck the data, clutch by clutch, and consider the importance of other factors besides myxomatosis that may
have altered clutch-sizes.
During drought, one would expect both rabbits and native prey such as macropods to decline, so drought
reduces the breeding success of eagles (Ridpath & Brooker 1986). However, rabbit control, such as RHD,
can result in an increase in native animals including macropods (Sandell & Start 1999), so we should
consider the heretical notion that reducing rabbit numbers in non-drought years could increase the breeding
success of raptors such as eagles or Barn Owls Tyto javanica that rely on macropods and/or other native
mammals for breeding.
References
Aumann, T. (1988). The diet of the Brown Goshawk, Accipiter fasciatus, in south-eastern Australia. Australian
Wildlife Research 15: 587–594.
Baker-Gabb, D.J. (1982). Comparative ecology and behaviour of Swamp Harriers Circus approximans Spotted
Harriers C. assimilis and other raptors in Australia and New Zealand. Ph.D. thesis, Monash University, Melbourne.
Baker-Gabb, D.J. (1984). The breeding ecology of twelve species of diurnal raptor in north-western Victoria.
Australian Wildlife Research 11: 145–60.
Edwards, G.P., Dobbie, W. & Berman, D.M. (2002). Warren ripping: its impacts on wild European rabbits and other
wildlife amid the establishment of rabbit haemorrhagic disease. Wildlife Research 29: 567–575.
Edwards, G.P., Dobbie, W. & Berman, D.M. (2002). Population trends in European rabbits and other wildlife of central
Australia in the wake of rabbit haemorrhagic disease. Wildlife Research 29: 557–565.
Leopold, A.S. & Wolfe, T.O. (1970). Food habits of nesting Wedge-tailed Eagles, Aquila audax, in south-eastern
Australia. CSIRO Wildlife Research 15: 1–17.
Newsome, A., Pech, R., Smyth, R., Banks, P. & Dickman, C. (1997). Potential impacts on Australian native fauna of
rabbit calicivirus disease. Report to the Australian Nature Conservation Agency, Canberra.
Olsen, J., Fuentes, E., Judge, D., Rose, A.B. & Debus, S.J.S. (2010). Diets of Wedge-tailed Eagles Aquila audax and
Little Eagles Hieraaetus morphnoides breeding near Canberra, Australia. Journal of Raptor Research 44: 50–61.
Olsen, P.D. & Marples, T G. (1992). Alteration in clutch size in raptors in response to changes in prey availability:
evidence from control of a broad-scale rabbit infestation. Wildlife Research 19: 129–135.
Parker, B.D., Hume, I.D. & Boles, W.E. (2007). Diet of breeding Wedge-tailed Eagles Aquila audax in south-central
Queensland. Corella 31: 50–62.
Ridpath, M.G. & Brooker, M.G. (1986). The breeding of the Wedge-tailed Eagle Aquila audax in relation to its food
supply in arid Western Australia. Ibis 128: 177–194.
Sandell, P.R. & Start, A.N. (1999). Rabbit Calicivirus Disease Program Report 4: Implications for biodiversity in
Australia. A report of research conducted by participants of the Rabbit Calicivirus Disease Monitoring Program
and Epidemiology Research Program. Prepared for the RCD Management Group, Bureau of Rural Sciences,
Canberra.
Steele, W. & Baker-Gabb, D. (2009). A national community-based survey of the diurnal birds of prey (BOP Watch).
Boobook 27: 23–24. [Abstract.]
Jerry Olsen
Journal of the Australasian Raptor Association
36
Boobook 31(2) July 2013
Do Australian Barn Owls nest in barns?
Pizzey & Knight (2007) and Simpson & Day (1999) make no mention of Barn Owls Tyto javanica nesting in
buildings. Debus (2009, summarising HANZAB) said they nest in buildings [which HANZAB said includes
‘cavities… in disused buildings’ and ‘shelves in roofs and walls of buildings –Ed.]. Hollands (1991, 2008)
said that the vast majority of nests were in trees, but some were in buildings. Though he described a Barn
Owl nesting in a vacated observation hide, a hide could be seen by owls as an artificial nest tree.
McLaughlin (1994) described a nest in a hayshed. However, Fleay (1968) argued that farmers should save
the large trees on their farms to attract Barn Owls which would control rodents, but he didn’t record wild
pairs nesting in buildings. König & Weick (2008), describing Tyto delicatula in Australasia, said they nest
in ‘natural cavities, chiefly in hollow trees’, which ignores the evidence for Barn Owls nesting in churches
and other buildings on Sumba in nearby Indonesia (Olsen et al. 2009). Olsen (2011) said ‘...it is not clear
why Barn Owls routinely nest inside buildings around the world, even on small islands like Sumba, but not
in Australia.’ [Maybe it has to do with time since buildings have existed in Australia –Ed.]
In Australia, Barn Owls commonly roost in buildings, as do some other species of Australian owls, for
example Southern Boobooks Ninox novaeseelandiae, and there seem to be published stories of people
finding Australian Barn Owls nesting in barns and churches as they do in Indonesia and Europe. However,
can anyone provide clear photographic evidence showing a brood of Barn Owl nestlings or a clutch of eggs
in a barn or church in Australia? Why is barn- and church-nesting so common in islands to Australia’s north,
but so rare in Australia?
References
Debus, S. (2009). The Owls of Australia: A Field Guide to Australian Night Birds. Envirobook, Sydney.
Fleay, D. (1968). Nightwatchmen of Bush and Plain. Jacaranda Press, Brisbane.
Higgins, P.J. (Ed.) (1999). Handbook of Australian, New Zealand & Antarctic Birds, Volume 4: Parrots to Dollarbird.
Oxford University Press, Melbourne.
Hollands, D. (1991). Birds of the Night. Reed, Sydney.
Hollands, D. (2008). Owls, Frogmouths and Nightjars of Australia. Bloomings Books, Melbourne.
König, C. & Weick, F. (2008). Owls of the World, 2nd edn. Christopher Helm, London.
McLaughlin, J. (1994). Aspects of the ecology and behaviour of the Barn Owl Tyto alba (Scopoli) in the mallee wheatbelt of north Victoria, Australia. MSc thesis, La Trobe University, Melbourne.
Olsen, J. (2011). Australian High Country Owls. CSIRO Publishing, Melbourne.
Olsen, J., S. Trost, & S. D. Myers 2009. Owls on the Island of Sumba, Indonesia. Australian Field Ornithology 26: 2–
14.
Pizzey, G. & Knight, F. (2007). The Field Guide to the Birds of Australia, 8th edn. HarperCollins, Sydney.
Schodde, R. & Mason, I.J. (1980). Nocturnal Birds of Australia. Lansdowne Press, Melbourne.
Simpson, K. & Day, N. (1999). Field Guide to the Birds of Australia, 6th edn. Penguin, Melbourne.
Jerry Olsen
Zygodactyl toe arrangement in raptors
The biggest difference between the feet of owls and those of diurnal raptors, except ospreys Pandion spp., is
that owls have a ‘reversible’ outer toe. They can perch with three toes pointing forward and one pointing
back, the usual ‘anisodactyl’ manner of most birds, including falcons, eagles and kites, or they can swing the
outer toe behind them, parallel to the rear toe, and perch with two toes pointing forward and two facing
backwards, a ‘zygodactyl’ arrangement (see Figure 1). In Hawks, Eagles & Falcons of North America Paul
Johnsgard (1990) defined anisodactyl as ‘an avian foot arrangement in which one toe (the 1st) is oriented
posteriorly, and the other three anteriorly’ (p. 338). In other words, the rear toe, 1, opposes toes 2, 3 and 4.
He defined zygodactyl as ‘an avian foot arrangement in which two toes (1st and 4th) are facultatively (as in
owls) or permanently oriented posteriorly and the other two (2nd and 3rd) anteriorly; typically only of
Ospreys among species in this book’ (p. 352). Facultative means ‘optional’ or ‘discretionary’, the antonym
of obligate, so toes 1 and 4 can optionally oppose toes 2 and 3, or not. By definition, Johnsgard does not
include Elanus kites such as the White-tailed Kite Elanus caeruleus as having a facultatively zygodactyl toe
arrangement, nor does Dunk (1995) in his species account of the White-tailed Kite.
Journal of the Australasian Raptor Association
Boobook 31(2) July 2013
37
Figure 1. Toe arrangements in raptors: anisodactyl
(upper left), zygodactyl (upper right), part-zygodactyl
(lateral 4) (bottom left). Toes on left foot are labelled
1–4.
Some have argued that owls have evolved this
special advantage over other raptors to better
clutch and carry heavy prey. It is possible,
however, that owls are taxonomically close to
birds like woodpeckers that already had two toes
forward and two toes backward; the 2 × 2 toe
arrangement evolved first and the hunting
advantage for owls evolved second, though Olsen
(2011) questioned whether the zygodactyl
arrangement was truly a hunting advantage for
owls. All diurnal raptors except ospreys seem to
get along fine without it. Owls could have a
reversible outer toe that swings forward from a
zygodactyl arrangement into an anisodactyl
position (three toes forward, one back) for holding
small prey. If you watch Southern Boobooks
Ninox novaeseelandiae or Little Owls Athene
noctua eating invertebrate prey in one foot, they
use an anisodactyl toe arrangement.
Tsang (2012) argued that Black-shouldered Kites Elanus axillaris can rotate the outer toe to a zygodactyl
arrangement, contra Johnsgard (1990), citing photographs in Cupper & Cupper (1981), Hollands (1984) and
comments in Negro et al. (2006) as evidence. However, photos of Black-shouldered Kites I looked at, in
collaboration with Geoffrey Dabb and Susan Trost, did not show zygodactyl arrangement in this species; that
is, the outer toe does not rotate back parallel to the rear toe, as in owls and ospreys.
Owls commonly perch using a zygodactyl toe arrangement, two toes forward, two back. But if you watch
owls hunting, they seldom catch ground prey using a zygodactyl arrangement, they mostly catch prey with
toe 1 opposing toes 2, and 3, the outer toe, 4, at a 90-degree angle to toes 1 and 3, an arrangement that could
be termed ‘part-zygodactyl’, or ‘lateral 4’ (Figure 1). This arrangement is superior to a zygodactyl
arrangement because it gives a wider lateral spread of talons, but the inner toes (# 2) don’t spread and
overlap, don’t get in each other’s way. That is, the logo on the cover of issues of Boobook, the ARA logo, is
not a correct representation of the toe arrangement owls use when they hunt ground prey. It is interesting
that Elanus kites also use this form of toe arrangement, part-zygodactyl instead of zygodactyl, probably
because it is superior to the anisodactyl or zygodactyl arrangement. Geoffrey Dabb has pointed out that
harriers may also use it. Part-zygodactyl may have developed in species that already had a facultatively
zygodactyl toe arrangement (owls, ospreys) or anisodactyl toe arrangement (Elanus kites and harriers). Partzygodactyl may have arisen independently across taxonomically unrelated raptors.
Particular thanks to Leah Tsang, Geoffrey Dabb, Susan Trost and Stephen Debus for help with these ideas.
References
Cupper, J. & Cupper, L. (1981). Hawks in Focus. Jaclin Enterprises, Mildura, Vic.
Dunk, J. R. (1995). White-tailed Kite (Elanus leucurus). In Poole, A. (Ed.), The Birds of North America Online.
Cornell Lab of Ornithology, Ithaca: http://bna.birds.cornell.edu/bna/species/178
Hollands, D. (1984). Eagles, Hawks and Falcons of Australia. Nelson, Melbourne.
Johnsgard, P.A. (1990). Hawks, Eagles & Falcons of North America. Smithsonian Institution, Washington DC, USA.
Negro, J.J., Pertoldi, C., Randi, E., Ferrero, J.J., Lopez-Caballero, J.M., Rivera, D. & Korpimaki, E. (2006).
Convergent evolution of the Elanus kites and owls. Journal of Raptor Research 40: 222–225.
Olsen, J. (2011). Australian High Country Owls. CSIRO Publishing, Melbourne.
Tsang, L. R. (2012). Facultative zygodactyly in the Black-shouldered Kite Elanus axillaris. Australian Field
Ornithology 29: 89–92.
Jerry Olsen
Journal of the Australasian Raptor Association
38
Boobook 31(2) July 2013
ARTICLES
The Powerful Owls of Springfield
Over the last few months [of 2012] I’ve been observing a family of Powerful Owls in Springfield (NSW
Central Coast). I occasionally heard Powerful Owls Ninox strenua calling from Rumbalara Reserve (near
Gosford) over the last couple of years, and have seen them before in the Sydney region, so I waited in my
backyard late at night listening for owls and shining my spotlight over neighbours’ roofs. This story began
on 8 May when I first heard the pair of Powerful Owls courting on the ridge near the Mouat Trail. I didn’t
hear them much after this, until one night in September. I was in the backyard at about 2200 h when I saw
something fly over the house towards a neighbour’s property. Shortly afterwards I heard a soft ‘woo hoo’
coming from the same area. Upon call playback, the female landed in the Blackbutt in my backyard seconds
later. She called earnestly for several minutes before flying ~50 m away, where she continued to call from a
low tree for ~20 minutes. Many backyard Powerful Owl sightings soon followed. On 20 November at
~2230 h I heard a high-pitched trilling call from the trees just beyond my back fence. Initially thought to be
a Ringtail Possum, it was louder and more repetitive, and by spotlight I found a juvenile Powerful Owl
sitting with its parents on a branch ~12 m high. Once they were illuminated, one adult flew into the
adjoining tree and out of sight, while the juvenile flew a short distance in the opposite direction. The
remaining adult stayed on the perch and then I was able to see that it was feeding on a Rainbow Lorikeet
Trichoglossus haematodus. The juvenile kept trilling for ~10 minutes in the nearby tree, until the adult with
the Lorikeet flew towards it. I couldn’t see exactly where it landed, but from the approximate spot I heard a
tapping sound – like something hard on wood (almost like a Kookaburra tapping its bill) at the rate of about
one tap per second. I couldn’t see how the owl was making the sound, and owl experts Rod Kavanagh and
David Bain do not know of any instances where Powerful Owls have made similar sounds before by tapping
their bill or prey on a branch. [Probably bones snapping as the adult dismembered the prey, or the
Lorikeet’s head/bill clunking on the perch as the owl pulled at the carcass –Ed.] Over the next week, I
located the juvenile on most nights by its distinctive and repetitive call. Some nights I could see the parent
and young from my backyard; on other occasions several hundred metres down the road, sharing a possum
kill in a roadside tree, unperturbed by passing cars or the sounds of the TV from a nearby house. These
Powerful Owls have adapted well to life in the suburbs. Next year, the breeding pair will be included in the
studies for the Powerful Owl Project, and it is hoped that their nest hollow will be located.
Nick Carson, Birding NSW Newsl. 255, Feb. 2013: 11
(here edited and abridged)
Square-tailed Kites’ response to fire
Square-tailed Kites Lophoictinia isura returned to Baradine (North-west Slopes of NSW, adjoining the
Pilliga Scrub) in 2005 after an absence of about 12 years. My first record of their nesting was compiled in
1981. I have a photograph of three eggs in one nest, and another of two fully fledged young in another nest
of the following year. In 2005 they built the nest in a very atypical situation in the heavy forks of a River
Red Gum Eucalyptus camaldulensis in the Baradine Creek, just east of the town. They fledged two young,
but the nest fell out of the tree soon after. The next year they selected a different site, in another Red Gum,
but the nest did not look secure. They again fledged two young before that nest also fell from the tree. Just
after the nest had fallen, among the sticks I found a still-fresh fledgling honeyeater, thus revealing that in the
post-fledging stage the Kites used the nest as a feeding platform, and still fed their young on fledgling
honeyeaters.
The following year (2007) the Kites built their nest on the opposite side of the same tree, but in a secure
position ~80 m from the town-side bank of the creek, fully visible to observers, and far enough away to
comfortably ignore any birders taking advantage of such an opportunity to see Square-tailed Kites.
This nest was used successfully for the next four years, until 2011 when disaster struck. The local Fire
Service decided that the build-up of long grass etc. in the creek bed posed a risk for the town, in the event of
a summer fire. They carried out a controlled burn on 5 November, when the Kites were brooding young
Journal of the Australasian Raptor Association
Boobook 31(2) July 2013
39
[incredible that they were allowed to do this to a threatened species at that critical time –Ed.]. The area
around the tree was well watered, to avoid any unnecessary heat under the nest. Despite the fact that
sometimes the nest could not be seen for smoke, the female did not at any time leave. However, the year
proved to be a failure; no young were reared. I was absent from the town soon after the burning, so did not
observe the immediate reactions of the Kites at that stage. The Kites did not return to the nest in 2012, and
so a wonderful opportunity to observe these beautiful, quiet raptors has been lost.
David Johnston, Tamworth Birdwatchers Newsl. 147, Sept. 2012: 11–12
(here edited and abridged)
FIELD NOTES
Square-tailed Kite taking wasp nest
On the morning of 1 February 2013, at Anstead on the southwestern outskirts of Brisbane (Qld), I saw a
Square-tailed Kite Lophoictinia isura fly up into a large tree. I didn’t have binoculars, but it became clear
the Kite had ‘caught’ something and was feeding on it. It then dropped a large piece of its prey, which I
retrieved. The object was part of a wasp’s nest, which the Kite had found and was now tearing apart,
presumably searching for the larvae in the nest. Searching for larvae in a wasp nest would indicate that the
Kites know the nests contain food, and either deliberately seek them out or take them opportunistically.
Nick Leseberg
Birding-Aus 01.02.2013 per Greg Clancy & Shirley Cook
…since HANZAB there have been several accounts of Square-tailed Kites taking nests of the paper-wasp
Polistes sp. (Aust. Birds 26, 1993: 104–118; Aust. Bird Watcher 18, 2000: 233–240; 270–273), culminating
in the note by Hobson (2006, Aust. Field Ornithology 23: 184–185) characterising the Kite as Australia’s
‘honey-buzzard’ both behaviourally and genetically. (Ed.)
Square-tailed Kite juvenile
At Tingha near Inverell on the NSW Northern Tablelands, on 13 February 2013 at ~1030 h EST, I
fortuitously flushed a juvenile Square-tailed Kite Lophoictinia isura from a perch near its nest. The nest was
a weather-battered, flat stick platform (after a cyclone in the preceding fortnight), ~9 m up in the nearhorizontal, multiple fork of a Yellow Box Eucalyptus melliodora, near the edge of extensive (100s of ha)
eucalypt woodland on the edge of town. The young Kite, obviously recently fledged, was fully grown, adult
in wing and tail proportions and competent in flight, but still using the nest as a feeding platform, judging by
the amount of fresh whitewash below the nest despite the recent heavy rain. The Kite had a large bulging
crop, suggesting a substantial vertebrate meal, and under the nest were the older remains of a Crimson
Rosella Platycercus elegans (bleached skull and bunch of weathered tail-feathers) from a previous meal. (It
was a typical Kite nest, not e.g. Brown Goshawk or Little Eagle). From fledging dates of the Kite in
northern NSW (November–December), the juvenile’s advanced stage of development and its large meal, I
believe it was fledged more than a month and still being fed at the nest by the adults. In support of this
interpretation are the studies cited above and also in Aust. Bird Watcher 19, 2001: 28–43 and 2002: 184–193;
and Aust. Field Ornithology 20, 2003: 94–104 and 21, 2004: 141–157. Combined, these studies record postfledging dependence periods of up to 2 months (discounting much shorter periods involving death, or
probable death, of the fledgling Kite). The Crimson Rosella is almost a record for the Kite’s avian prey size,
among prior records of adult Eastern Rosella and Rainbow Lorikeet (as well as less dangerous Spotted Dove
and Crested Pigeon). These parrots raise the question of how the small-footed Kite deals with prey that
could severely damage its feet, unless quickly killed when seized.
Stephen Debus
Journal of the Australasian Raptor Association
40
Boobook 31(2) July 2013
Black Falcons hunting
On central Yorke Peninsula (SA), in early October 2012 in mid morning, I observed a Black Falcon Falco
subniger make a low-level direct flying attack at a flock of Common Starlings Sturnus vulgaris that were on
the ground in a grazing paddock. The Falcon missed its intended prey as the Starlings flushed, bunched and
rose above it. Unfortunately, I missed the initial stages of the search and attack phase, but the habitat was
very open (cleared), and the Falcon was already approaching the flock rapidly at low level, across open
ground, when I first saw it.
In mid 2012, Brian Stone told to me that a pair of Black Falcons regularly hunted his free-flying domestic
Rock Doves Columba livia on his farm near Breeza, on the Liverpool Plains of NSW. He described how the
pair repeatedly co-operated to catch the pigeons, and remarked on the speed of the Falcons. Usually, one
high-flying Falcon kept the pigeons distracted while the other Falcon made a low-level surprise attack from
the side; in one instance, one Falcon landed in a tree, walking along the branch to flush sheltering pigeons for
the other Falcon waiting in the air, but the pigeons were reluctant to leave the tree.
Stephen Debus
Little Eagle attempts to catch Glossy Black-Cockatoo
Lest it remain ‘lost’ to raptor students, the following noteworthy episode is here extracted from Matt
Cameron’s book Parrots: The Animal Answer Guide (2012, Johns Hopkins Univ. Press, Baltimore, USA),
p. 78, with some pertinent details added from his preceding sentences. The site is inferred to have been
Matt’s cockatoo study site in Goonoo National Park near Dubbo, NSW.
‘I observed an unsuccessful attack by a Little Eagle Hieraaetus morphnoides on a foraging group of Glossy
Cockatoos Calyptorhynchus lathami in central NSW. The eagle appeared to locate the group by soaring,
then launched a surprise attack below the forest canopy. This attack might have been successful if the
cockatoos had not taken off and flown directly over my head, causing the eagle to veer away when it became
aware of me.’
Matt Cameron
Black Falcon attacking Starlings
On 23 March 2013 at 1355 h, while driving south along the Bacchus Marsh–Balliang Road (Vic.) and
~200 m from the junction of the Rowsley–Glenmore Road, I observed a flock of Common Starlings Sturnus
vulgaris being pursued by a female Black Falcon Falco subniger. The most amazing thing was seeing the
Falcon attack the Starlings in a horizontal fashion, and instantly roll into a vertical descending attack with no
loss of speed to single out a lone Starling – simply amazing! The attack was unsuccessful, and the Falcon
departed.
David Whelan
Black Falcon hunting Galahs
In February 2013 at the DPI Research Station, Calala, Tamworth (NSW), I saw a large group of Galahs
Eolophus roseicapillus swooping and calling, and wondered what was upsetting them. I then saw a Black
Falcon Falco subniger just on the edge of the group, shadowing their moves, which was why they were
carrying on so. He (or she) was probably hunting the Galahs, although I didn’t see the Falcon catch any
prey.
Jan Hosking
Tamworth Birdwatchers Newsl. 152, April 2013: 3
Journal of the Australasian Raptor Association
Boobook 31(2) July 2013
41
Black Falcon attacking Black-shouldered Kite
On the afternoon of 9 April 2013, along the road between Ashford and Bonshaw (northern inland NSW), I
glimpsed through the vehicle windscreen a large, dark bird swooping a smaller bird high in the air. In the
time I could pull over and get out to watch, the interaction had been in progress for several swoops, and I
didn’t see how it started. It was a Black Falcon Falco subniger repeatedly stooping vertically and
determinedly (power dives with wing-beats) at a Black-shouldered Kite Elanus axillaris, which was not
carrying prey. The Kite nimbly dodged each stoop, which appeared predatory in intent, and after five or six
stoops since I had stopped the car (or maybe ten in total), the Falcon noticeably tired and slowed, and headed
off on a long descending glide. The Kite then turned the tables and repeatedly swooped the retreating
Falcon, which twice did a rather feeble half-roll and parry with its feet. The Falcon eventually landed on a
dead-topped eucalypt away off in a paddock, and I lost sight of the Kite. The behaviour was such that if the
victim had been a non-raptor, I would have instantly concluded that the Falcon was trying to catch it. There
are records of Black Falcons preying on Elanus kites (both species), e.g. in HANZAB. The above episode
reminded me of a much earlier one (decades ago) of a Black Falcon similarly stooping repeatedly at a flying
Nankeen Kestrel Falco cenchroides, which didn’t look good for the dodging, tiring Kestrel (I couldn’t see
the outcome, but there are also records of Black Falcons taking Kestrels).
Stephen Debus
Small falcons and dragonflies
It is well known that the Australian Hobby Falco longipennis is partial to dragonflies, which it takes on the
wing after a swift, direct approach. The predilection of Hobbies for these insects appears to be pronounced
in some individuals, as demonstrated during preparation of an injured first-year female for release. Between
January and August 2012, this bird almost exclusively took individuals of the relatively large (and common)
Australian Emperor Hemianax papuensis over a sportsfield in Huntingdale near Perth (WA). A resident pair
of Hobbies was also observed feeding on dragonflies at this location. On 25 August 2012, I observed an
adult male Nankeen Kestrel Falco cenchroides hawking the same species of dragonfly from a low perch at
the edge of Forrestdale Lake. The bird appeared to target dragonflies that were in copula, thus increasing its
chances of success on such larger, slower-moving (and distracted) targets. The Kestrel darted out and
snatched these dragonflies with one foot, landed on the ground, then returned to the perch to feed on the
insect that was grasped. This particular bird appeared to have mastered this technique. These observations
suggest that the larger dragonflies may be an important food source for both these small falcons in the Perth
area.
Warren Goodwin
Brown Goshawk and Brown Falcon scavenging
During attempts to capture Wedge-tailed Eagles with kangaroo carcasses as bait, for my honours project near
Canberra in the ACT (see abstracts, p. 48), I placed motion-sensitive cameras at the bait and bownet trap.
On 27 August 2012, at Woodstock Nature Reserve, Coree at ~1715 h, the camera captured a female Brown
Goshawk Accipiter fasciatus (either second-year or adult) feeding on the roo carcass; she mantled against an
approaching raven Corvus sp. (on the ground) and continued feeding undisturbed for over 10 minutes. On
29 August 2012, at Rob Roy Nature Reserve, Theodore at ~1000 h, the camera captured an adult female
Brown Falcon Falco berigora feeding on the roo carcass; she successfully rebuffed an approaching
Australian Raven C. coronoides and fed for a further 15 minutes then stepped aside, which allowed the
Raven to feed. Neither bait site was near any Wedge-tailed Eagle nests.
Felicity Hatton
…these records provide additional examples of carrion-feeding by these two raptors, and a new food source
(kangaroo; see HANZAB). (Ed.)
Journal of the Australasian Raptor Association
42
Boobook 31(2) July 2013
Grey Falcon prey records
Near Lake Altiboulka, south-west of Wanaaring (far north-western NSW) in March 1988, I saw a Grey
Falcon attacking a group of Chestnut-crowned Babblers Pomatostomus ruficeps. In October 2010, at Fort
Grey in Sturt National Park (north-west NSW), I saw two Grey Falcons (I have photographs, referred to
Jonny Schoenjahn) feeding on a Cockatiel Nymphicus hollandicus.
Ian McAllan
Nest defence by Black-breasted Buzzards
I’ve been to many (>100) active Black-breasted Buzzard Hamirostra melanosternon breeding sites in the
south-west of the Northern Territory, and at some nests one or both adults defend ferociously against human
intruders anywhere within several hundred metres of the nest tree, right through to the post-fledging period.
At other (most) nests, there’s no such defence at all. Buzzards often use nests (successfully) in mostly-dead
trees that offer little or no canopy cover, and they seem better able to breed successfully than are other
raptors in hot, dry seasons in central Australia.
Tom Aumann
Black Falcon associating with Spotted Harrier
On 26 April 2013, at the Werribee sewage treatment plant (Vic.), Tom Fletcher and I saw two raptors sitting
on a fence within 2 m of each other. One was a Spotted Harrier Circus assmilis, the other a large (?female)
Black Falcon Falco subniger. When disturbed by a passing vehicle they flew off, the Falcon seemingly
shadowing the Harrier by staying a few metres behind it. It appeared that the Falcon was using the Harrier to
flush potential prey. HANZAB mentions Black Falcons taking prey flushed by other raptors. At the moment,
it appears that there are more Spotted Harriers around this part of Victoria than usual.
Hugo Phillipps
*************
ARA CONFERENCE UPDATE
The registration deadline for the ARA conference (Adelaide Zoo, 9–11 August) is Friday 19 July, so there is
still plenty of time (but please register asap); we hope to see many members there. If you haven’t received a
flyer, you can download a program and registration form from the BirdLife website. And would presenters
please include the key take-home messages (i.e. main findings) in their abstracts (for Boobook), and bring a
completed draft paper (for submission to a journal editor) of their talk or poster to the conference, to speed
up the appearance of their work in the scientific literature. Registration starts at 5 pm on Friday the 9th,
before the 7 pm function, and at 8 am on the 10th (for a 9 am start of talks).
STOP PRESS: Anita Turton advises that the following link will take you to the Birds SA website. This site
will constantly be updated with information needed by conference attendees and speakers. Please keep a
check on it until the conference date arrives.
http://birdssa.asn.au/index.php/australasian-raptor-association-conference
Journal of the Australasian Raptor Association
Boobook 31(2) July 2013
43
BOOK REVIEW
Birds of Prey of Australia – A Field Guide (2nd edn) by Stephen Debus. CSIRO Publishing, Melbourne,
2012. Softcover, 15 × 21.5 cm, col. illustrations and photos, maps, 208 pp. RRP $40 (20% discount + p&p
to BirdLife members if ordered through CSIRO).
The title differs from the first edition solely by dropping ‘The’ as the first word in the title. But there the
resemblance ends. The first edition was basically a rehash of the field identification components of diurnal
raptors from Volume 2 of the Handbook of Australian, New Zealand and Antarctic Birds (HANZAB) with
the addition of a few colour photographs. Sure, it was in basic field guide style and size, but was it really a
specialists’ field guide and was it any better for field ID than the general Australian bird field guides of the
day? I had my doubts!
Now we have the second edition – well, it wouldn’t be appropriate to just say it’s ‘a different kettle of fish’ –
I believe that Stephen Debus has now created a true specialist field guide to the diurnal raptors of Australia.
In the preface we are informed that the impetus for a second edition came from demand for its 2001
predecessor, even though data presented in it were more than 15 years out of date. But Stephen wasn’t
satisfied with a cosmetic update of the original publication. He did a complete revision, rewrite and
reformatting that incorporates new knowledge and a new and impressive concept to compare species that
might be confused in flight. The new edition still incorporates a concise overview of raptor biology, but it
has also converted the original HANZAB extract into a comprehensive guide to the field diagnostic characters
of all of Australia’s diurnal raptors in a far more useful and informative format.
Each species has a double-page spread that presents illustrations, including flight profiles, size and plumage
descriptions of age classes, and also draws attention to similar species. This concept alone elevates the value
of the book to true field-guide status. But then the really exceptional concept of ‘split-images’ is introduced
to clearly illustrate differences between species that might be confused with each other.
The field-guide value is then enhanced even further by the inclusion of diagnostic in-flight photographs of all
species. This is followed by a handbook section that presents information on distribution, food and hunting,
behaviour, breeding, threats and conservation of each species. The final chapters discuss the broad threats,
conservation and the future for raptors and present a glossary and species-specific bibliography.
If you acquired the first edition you might be tempted to ignore an updated second edition. FAIL! Retire the
first edition to the bookshelf. You must have a copy of the second edition in the driver’s door pocket of your
vehicle.
Jeff Hardy, reprinted from Corella 37, 2013: 47
…the first edition had an imposed format (I was instructed to model it on Pauline Reilly’s Penguins of the
World, in OUP’s ‘HANZAB spin-off’ series). And credit where it’s due: it was John Manger of CSIRO
publishing who suggested the modern field-guide layout (double-page spread, illustrations opposite text) for
the second edition, and the split images were an adaptation of prior ideas by Nick Mooney and Greg
Czechura. For a more comprehensive and critical review, see Veerman, P. (2012), Canberra Bird Notes 37:
235–237. In response: of course the ‘longer/shorter middle toe’ of the Collared Sparrowhawk vs Brown
Goshawk refers to relative (not absolute) toe length, and I don’t think any other book has intended to imply
otherwise either. Another review (Australian Birdlife 1(4): 74) nominates a flaw as the Grey Falcon (which
the reviewer has admittedly never seen) illustrated the same size as the Grey Goshawk and Peregrine when it
(Grey Falcon ) is smaller, but (a) absolute size is a difficult criterion in the field; (b) one will almost never be
able to directly compare Grey Falcon and Grey Goshawk in the same view; (c) sexual size dimorphism
means that female Grey Falcons are larger than male Grey Goshawks (the respective males are nearly the
same size), and are the same size as male Peregrines; (d) the split images were intended to compare shape
(proportions) and plumage characters, not necessarily relative size. (SD)
Journal of the Australasian Raptor Association
44
Boobook 31(2) July 2013
Australian Bird Names: some raptor myths resurrected
Although not a review here in the usual sense, the newly published book Australian Bird Names: A Complete
Guide (I. Fraser & J. Grey, CSIRO Publishing, 2013) deserves some comment with respect to raptors.
Unfortunately, it resurrects and re-perpetuates some myths that have been scotched in the last 20–30 years.
Pacific Baza: the genus name Aviceda (‘bird-killer’) is said to be ‘not entirely a misnomer’, on the grounds
that it occasionally takes nestlings and very small birds. However, there are no published studies in support,
and among only two specific cases cited in HANZAB (one a Silvereye), the claim of domestic chicken has
since been discredited as most likely involving a misidentified accipiter.
Australian Hobby: ‘certainly takes ducks’?? It certainly does NOT, and all such claims refer to misidentified
Peregrines, as has long been pointed out in the journal literature (as indeed flagged by HANZAB). (Ed.)
RECENT LITERATURE
Journals
Animal Conservation 16 2013
Use of mixture models to characterize site quality in philopatric animals: a case study with Bonelli’s Eagle
(C. Chevalier et al.), 198–206.
AudioWings 14(2) Dec. 2012 (journal of the Australian Wildlife Sound Recording Group)
Observations and sonograms of the calls of Grey Falcon Falco hypoleucos (T. Baylis & F. van Gessel), 8–9.
Auk 130 2013
Genetic relationships among some subspecies of the Peregrine Falcon (Falco peregrinus L.), inferred from
mitochondrial DNA control-region sequences (C. White et al.), 78–87.
Life-history tradeoffs in Spotted Owls (Strix occidentalis): implications for assessment of territory quality
(M. Peery & R. Gutiérrez), 132–140.
Australian Birdlife 12(2) 2013
In the spotlight: the Powerful Owl (Anon.), 57. [Profile of BirdLife’s Powerful Owl project.]
Powerful poo (D. Bain), 58. [Report on project volunteers’ pellet workshop and dietary analysis; notes that
owl pellets are regurgitated, so the title must be (unfortunately inaccurate) editorial licence.]
Australian Field Ornithology 30 2013
Aerial diving display, with calling, by Black Falcon Falco subniger (D. Whelan), 103–105.
Do Tasmanian Southern Boobooks migrate? (J. Olsen & S. Debus), 106–108.
Australian Journal of Zoology 59 2011
Diet analysis of mammals, raptors and reptiles in a complex predator assemblage in the Blue Mountains,
eastern Australia (J. Pascoe et al.), 295–301. [Powerful Owl.]
Reversed sexual dimorphism and altered prey base: the effect on Sooty Owl (Tyto tenebricosa tenebricosa)
diet (R. Bilney et al.), 302–311. [Now depends on a narrower prey base of hollow-dependent arboreal
mammals.]
Behavioral Ecology & Sociobiology 67 2013
Is there a different response to winds during migration between soaring and flapping raptors? An example
with the Montagu’s Harrier and the Lesser Kestrel (R. Limiñana et al.), 823–835.
Journal of the Australasian Raptor Association
Boobook 31(2) July 2013
45
Biological Conservation 159 2013
Rescue of a small declining population of Spanish Imperial Eagles (M. Ferrer et al.), 32–36.
Biological Conservation 160 2013
Habitat selection by Black Kite breeders and floaters: implications for conservation management of raptor
floaters (A. Tanferna et al.), 1–9.
Bird Conservation International 23 2013
The value of the Black Harrier Circus maurus as a predictor of biodiversity in the plant-rich Cape Floral
Kingdom, South Africa (J. Jenkins et al.), 66-77.
Brokering a settlement between eagles and industry: sustainable management of large raptors nesting on
power infrastructure (A. Jenkins et al.), 232–246.
Bird Study 60 2013
Differential wintering area selection in Eurasian Marsh Harrier (Circus aeruginosus): a ringing recovery
analysis (M. Panuccio et al.), 52–59.
Breeding season diets of sympatric White-tailed Eagles and Golden Eagles in Scotland: no evidence for
competitive effects (D. Whitfield et al.), 67–76.
Condor 115 2013
DNA sequencing reveals patterns of prey selection in migrating Sharp-Shinned Hawks (J. Delong et al.), 40–
46. [From feathers of prey on beaks and feet of trapped hawks.]
Breeding performance of the Grasshopper Buzzard (Butastur rufipennis) in a natural and a human-modified
West African savanna (R. Buij et al.), 47–57.
Corella 37 2013
Diets of Wedge-tailed Eagles Aquila audax and Little Eagles Hieraaetus morphnoides breeding near
Canberra, 2008–2009 (J. Olsen et al.), 25–29.
Numbers of breeding Little Eagles Hieraaetus morphnoides near Canberra in relation to atlas counts (S.
Debus et al.), 30–32.
Declining Little Eagles Hieraaetus morphnoides and increasing rabbit numbers near Canberra: is secondary
poisoning by Pindone the problem? (J. Olsen et al.), 33–35.
Forktail 28 2012
Vocal divergence and new species in the Philippine Hawk Owl Ninox philippensis complex (P. Rasmussen et
al.), 1–20.
Migrating dragonflies: famine relief for resident Peregrine Falcons Falco peregrinus on islands (ChangYong Choi & Hyun-Young Nam), 149–151.
Brahminy Kites Haliastur indus fishing with Irrawaddy Dolphins Orcaella brevirostris in the Mekong River
(G. Ryan), 161–162.
Breeding ecology of the Northern Boobook Ninox japonica totogo in central Taiwan (Wen-Loung Lin et al.),
164–16
Ibis 155 2013
Honey Buzzard Pernis apivorus nest-site selection in relation to habitat and the distribution of Goshawks
Accipiter gentilis (A. Gamauf et al.), 258–270.
Birds of prey of the Kazakh Upland – indicators of steppe well-being (A. Barashkova et al.), 426–427.
Journal of the Australasian Raptor Association
46
Boobook 31(2) July 2013
J. Avian Biology 44 2013
Immigration stabilizes a population of threatened cavity-nesting raptors despite possibility of nest box
imprinting (J. Brown & M. Collopy), 141–148. [American Kestrel.]
Brown Tawny Owls moult more flight feathers than grey ones (P. Karell et al.), 235–244.
J. Raptor Research 47 2013
Is the long-term decline of Boreal Owls in Sweden caused by avoidance of old boxes? (T. Hipkiss et al.),
15–20. [No effect of age of nest boxes.]
Distinctiveness in the territorial calls of Great Horned Owls within and among years (K. Odom et al.), 21–
30. [Variation allows recognition of individual males and females; useful for long-term monitoring.]
Visible migration of Short-Toed Snake-Eagles: interplay of weather and topographical features (M. Panuccio
et al.), 60–68.
Close inbreeding and dispersal in Merlins: further examination (I. Warkentin et al.), 69–74.
Government-sponsored falconry practices, rodenticides, and land development jeopardize Golden Eagles
(Aquila chrysaetos) in western China (Ming Ma), 76–79.
Reversed sexual size dimorphism and prey size taken by male and female raptors: a comment on Pande and
Dahanukar (2012) (J. Olsen), 79–81.
Reversed sexual dimorphism and prey delivery: response to Olsen (S. Pande & N. Dahanukar), 81–82.
Sibling competition induces stress independent of nutritional status in broods of Upland Buzzards (R. Yosef
et al.), 127–132.
The effect of introduced species on raptors (K. Speziale & S. Lambertucci), 133–144. [Positive and
negative: plants and animals, variously as habitat/nest sites, prey, competitors, vectors of contaminants
etc. A key review paper, but it missed many Australian papers dealing with exotic prey species; it also
bizarrely classes quolls and monitor lizards (goannas) as exotics in Australia!]
Turkey Vulture breeding behavior studied with trail cameras (C. Rollack et al.), 153–160.
Feather corticosterone levels and carotenoid-based coloration in Common Buzzard (Buteo buteo) nestlings
(J. Martínez-Padilla et al.), 161–173.
Carotenoids and skin coloration in a social raptor (J. Blas et al.), 174–184. [Bare-part colour in sex and
social (breeder vs floater) classes of Black Kite.]
Characteristics and sexual functions of sky-dancing displays in a semi-colonial raptor, the Montagu’s Harrier
(Circus pygargus) (B. Arroyo et al.), 185–196.
Brightness features of visual signaling traits in young and adult Eurasian Eagle-Owls (C. Bettega et al.),
187–207.
Science 331 2011
Raptor nest decorations are a reliable threat against conspecifics (F. Sergio et al.), 327–329. [Nest-lining of
territorial Black Kites signals viability, territory quality and dominance of nest-owner; correlates with
age of owner.]
Sunbird 43(1) 2013
Observations on hunting and breeding behaviour of the Black Falcon (Falco subiger) (S. Debus & A.
Zuccon), 12–26.
Zootaxa 3635 2013
A new species of masked-owl (Aves: Strigiformes: Tytonidae) from Seram, Indonesia (K. Jønsson et al.),
51–61. [Seram population of supposed Lesser Masked Owl Tyto sororcula elevated to full species as
Seram Masked Owl T. almae on DNA and morphological evidence; taxa T.s. cayelii (Buru) and T.s.
sororcula (Tanimbar Is), and T. manusi (Manus Is.), probably conspecific with Masked Owl T.
novaehollandiae.]
Journal of the Australasian Raptor Association
Boobook 31(2) July 2013
47
Abstract from the Wind & Wildlife conference, Melbourne, October 2012
Results from ten years of eagle studies at the Bluff point and Studland Bay Wind Farms, Tasmania
Cindy Hull and Chris Sims, Hydro Tasmania (Australia)
Two species of eagle, the Tasmanian Wedge-tailed Eagle (WTE, Aquila audax fleayi) and the White-bellied
Sea-Eagle (WBSE, Haliaeetus leucogaster) are present on the Bluff Point and Studland Bay windfarms in
north-west Tasmania. These species have been intensively studied since the commencement of operations in
2002 and 2007, respectively, as part of compliance monitoring, targeted studies and trials of collision
mitigation techniques. Monitoring has included collision monitoring, breeding success surveys, and
movement and behaviour studies. Both species of eagle have continued to use the sites after the construction
and operation of the windfarms. The average collision rates for WTE were 1.64 and 1.05 per year, and for
WBSE 0.38 and 0 per year at Bluff point and Studland Bay, respectively (calculated up to 31 December
2011). This is below maximum rates estimated in the collision risk modelling conducted during the approval
process. The collision rate for WTE was constant across years (analysis could not be conducted on WBSE
due to small sample sizes), although the rate may be declining at Studland Bay. We have investigated the
data for the possibility of seasonal or other temporal patterns, but all evidence supports the theory that the
strikes are independent and random in time. A spatial analysis was not possible, again due to small sample
sizes. Eagles continued to breed at the sites, with some evidence that this was at a higher rate than nests
outside the windfarms. Studies of the behaviour and movement of eagles found a high avoidance of turbines,
but not 100%. The avoidance rate changed with development of the windfarm and whether turbines were
operational or not. Various strategies to reduce the eagle collision rate at these windfarms have been trialled,
with none yet found to be effective. The results of all studies and mitigation trials and key learnings will be
presented.
…see Nick Mooney’s abstract in Boobook 30(2), Dec. 2012: 54. (Ed.)
Abstracts submitted to the BirdLife Southern NSW Raptor and Owl Seminar, 23 March 2013
(some key results are appended, as applicable, from notes I took at the seminar –Ed.)
Progress in the Powerful Owl Project
David Bain
The Powerful Owl Project is a citizen science research project looking at the urban-based population of
Powerful Owls throughout the Sydney Basin. The project was initiated by a motivated member of the
public, with no formal science-based training. The project is now funded through the NSW Environmental
Trust and led by BirdLife Australia. The project is mapping all the known urban-based breeding territories
of Powerful Owls in the Sydney Basin, and looking at breeding success and nest-site fidelity in relation to
disturbance proximity, environmental variables and incidents such as car-strike. In addition, the project is
looking at long-term trends in diet, based on data collected over 10 years ago within Sydney. The project is
also focussed on developing education resources, aimed at land managers, community groups and school
children. These resources will engage on protection and management of habitat and education about the
value of urban biodiversity.
Some key results to 2012:
Sixty-nine volunteers are monitoring 84 sites, with 300 sightings logged in the database.
In 2012 there were 46 Owl territories in Sydney, with breeding in 22, producing 30 chicks, but 25 attempts
failed.
There were 10 car strikes in 2012 and 4–5 since, including adult deaths in the breeding season, representing
26% of territories, 7% of the Owl population (including floaters), and contributing to breeding failure.
In recent dietary trends, Common Ringtail Possums are down, Common Brushtails and flying-foxes are up,
birds are the same; other items include Sugar Gliders and Christmas Beetles.
Journal of the Australasian Raptor Association
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Boobook 31(2) July 2013
The Masked Owls of Lord Howe Island – maintaining an artificial balance
David Milledge
At least 40 Masked Owls were introduced to Lord Howe Island in the 1920s, and successfully established a
population that currently appears to number between 20 and 30 pairs. The species has successfully adapted
to the Island’s rainforest habitats, occurs at up to ten times its normal density, occupies small overlapping
home ranges between 75 and 230 ha, and appears to have relaxed its territorial behaviour. It feeds mainly on
introduced rats and mice, but also takes a variety of seabird and some terrestrial bird species. Roosts are in
dense canopies, tree hollows and crevices in epiphytes, and nests have been found in tree hollows and under
a rock overhang. The species has been implicated in the demise of the Lord Howe Boobook, but may
currently be preventing the extinction of several other endemic bird species. It is proposed to remove
Masked Owls from Lord Howe Island over the next three years, but this must be achieved coincident with
rodent eradication to avoid the effects of meso-predator release.
Some key results:
Masked Owls were said to have come from Tasmania, but at least some originated from the mainland (see
Boobook 31: 20); the population is thus of hybrid origin (two subspecies).
Diet includes the Lord Howe Currawong, Black-winged Petrel, White Tern, Sooty Tern and Buff-banded
Rail. The Owl is thus said to be a pest, but seabirds are increasing.
Notes on trapping methods and monitoring of post-fledging behaviour of a juvenile Wedge-tailed
Eagle tracked using satellite telemetry in the ACT
Felicity Hatton
Satellite tracking has been used successfully overseas in the conservation biology of many raptor species, yet
has not been utilised in the research of any Australian eagle species. Despite the wealth of knowledge on the
Wedge-tailed Eagle Aquila audax, information on home-range size has been limited to estimates from visual
observations. The minimum convex polygon (MCP) and fixed kernel methods to estimate home-range size
have yet to be utilised in studies of this species. This study aimed to serve as a pilot study to investigate
effective trapping methods and establish methodologies on the use of satellite telemetry technology in the
quest to fill in some of the aforementioned gaps. Trapping aimed at capturing adult eagles was carried out in
Canberra from September to December 2012 with limited success, through the use of a bownet trap baited
with a macropod carcass. A juvenile Wedge-tailed Eagle was captured by chance in November 2012, and
released fitted with a harness and a Minitrack satellite Platform Transmitter Terminal (PTT) unit for homerange analysis and study of post-fledging behaviour. Fixes of the eagle’s position were taken at 90-minute
intervals for four months to cover the post-fledging dependence period. The PTT also provided activity data
on the movements of the tagged individual. This included daily movement patterns such as acceleration and
altitude, allowing analysis of time spent flying and perching. Behaviour was analysed by comparison of
observations with activity data combined with GPS position data, to identify areas frequented by the tagged
individual during foraging and resting, providing information on habitat utilisation.
Key results:
The juvenile increased its home-range size from week 1 to week 7, with a shift in home range; by week 7 it
was using ~1 km2.
Suburban survivor? – breeding, and decline, of the Little Eagle around Canberra
Geoffrey Dabb
This presentation uses maps, graphs, and photos (and video, if time permits) to tell the story (shortly) of the
Little Eagle Hieraaetus morphnoides in the north of the ACT, in particular around Canberra. A main theme
is the apparent collapse of breeding numbers over the last 25 years. Nesting-based records, mainly from
Jerry Olsen’s group, are compared with Canberra Ornithologists Group data over 30 years. COG data are
Journal of the Australasian Raptor Association
Boobook 31(2) July 2013
49
explained and examined. An update is given of nesting records already published. The weight to be given to
each of the possible causes suggested for the apparent collapse (e.g. secondary poisoning by the pesticide
Pindone) remains uncertain. The state of play on the ACT government’s draft action plan for this threatened
species, and related matters, are considered.
Key results:
The population has gone from 13 known territories in 1992 to one breeding pair in the ACT in 2011 and two
in 2012.
The demonstrated distribution pattern of nests suggests that one or two nests in the ACT are missed each
year.
As well as loss of habitat, two nest sites were bulldozed and three were lost, possibly to competition from
Wedge-tailed Eagles.
Little Eagles may be nesting nears the suburbs, where there are no Wedge-tailed Eagles.
Many Little Eagle sightings may now be of transients.
There may be increasing harassment of Little Eagles, particularly by magpies and ravens.
What’s on the menu? The breeding diet of the Parramatta River Sea-Eagles
Judy Harrington
Sea-Eagles are recorded taking a variety of opportunistic prey, including birds, reptiles, fish, mammals,
crustaceans and carrion. Observations of this breeding pair have indicated their main prey is fish and Silver
Gulls. Fish include mullet, bream, whiting and eels. Eels are easily caught in the nearby wetlands, which
are periodically drained for control of Gambusia (Mosquito Fish). Silver Gulls are common along the river
and have a breeding colony on old boats in Homebush Bay. The eagles catch adult, juvenile and nestling
gulls. Both adults have been recorded bringing prey to the nest. This pair has not been observed pirating
prey from other species.
Over the years, several Sea-Eagles have been found dead in the Parramatta River area. Prior to 2004, only
one chick in fifteen years had been successfully raised. Following the death of a pair of breeding eagles in
2004, necropsy and chemical analysis of tissues was undertaken in order to determine the cause of death.
This report recommended further study of Sea-Eagles at Homebush Bay to provide information relevant to
the management of avifauna at the site.
In spite of its size and relative abundance on the east coast, little is known about the breeding biology of SeaEagles. These eagles have been living and interacting in close proximity to urban life for their hunting range
and daytime roosts. The location of the nest, within the restricted-access Nature Reserve, means that
breeding is undisturbed. The current pair has successfully raised young to fledging in five consecutive years.
Although the nest branch collapsed in early February 2011, the adults have continued to occupy the
surrounding territory and built further two nests in the same area. The eagles are studied using video CCTV
cameras and by limited physical observation. Breeding diet is being studied by observations at the nest from
the cameras, incidental observations along the river and in Homebush Bay, and by collecting prey remains in
the nest area.
Analysis of their breeding behaviour is continuing and has indicated that both adults bring prey to the nest.
In mid August, when the eaglets were nearly 8 weeks old, the nestlings became entangled in fishing line and
unfortunately one had swallowed a hook with line attached. At this stage of their development, the eaglets
were self-feeding and the adults were only making a few short visits to the nest, with prey. The adults,
particularly the female, responded to the distress calls of the nestlings with many visits to the nest, bringing
at least seven prey items to her young. Fortunately, the eaglets were rescued and both survived to fledging.
Analysis of our observations continues and is revealing much valuable information on the behaviour of these
urban eagles.
Additional results:
Prey items of this pair have included flying-fox, hare, rat, possum, cat, turtle, Common Bluetongue and
lorikeet.
Journal of the Australasian Raptor Association
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Boobook 31(2) July 2013
INTERNATIONAL NEWS
Powerlines contributing to demise of vultures in South Africa
…the main reasons [for the decline of the Cape Vulture] are considered to be a shortage of food (carrion),
inadvertent poisoning during predator control operations by small stock farmers, electrocution on, and
collision with, powerline infrastructure, drowning in high-walled cement farm reservoirs, illegal harvesting
for the traditional medicine industry, and disturbance by humans at breeding sites… Although it has been
known for more than 40 years that powerline infrastructure is an important cause of Cape Vulture deaths in
South Africa, until recently no satisfactory attempt has been made to determine the impact of the ongoing
deaths from this source on the population dynamics of this species. Now, a research project… has provided
the first scientific evidence that such infrastructure can and does have a significant negative impact on the
population of this species…
The study revealed that 22 255 km of ‘unsafe’ or potentially ‘unsafe’ distribution lines (i.e. lines that
comprise infrastructure that is known to electrocute vultures) still exist in the commercial farming areas of
the Eastern Cape. These particular lines electrocute close to 70 vultures every year, this representing nearly
3.5% of the total number of Cape Vultures that remain in the region. With the aid of a simple population
model, the researchers were able to predict that, at this annual mortality (death) rate, the vulture population
in the commercial farming areas will crash to extinction, as a result of electrocution alone, within a 25–30
year period. This outcome is known to be highly conservative, given that vulture deaths from collisions with
powerline infrastructure (which occur, at an unknown frequency, on transmission and distribution lines
throughout the electrified parts of the Eastern Cape) were not considered in the model. In addition, all the
other major mortality factors listed above, which are additive to powerline-related mortality, were not
considered in the analyses.
Notably, in those parts of the Eastern Cape where the distribution networks comprise mainly ‘safe’
infrastructure and therefore where the electrocution threat is low (namely the communal tenure areas where
subsistence farming prevails), the Cape Vulture is predicted to undergo slow but positive growth over the
next 50 years, if the other forms of unnatural mortality are ignored. The outcome of the study briefly
reported on above confirms that ‘unsafe’ powerline infrastructure is a major threat to the continued existence
of the Cape Vulture (and indeed to other large birds, such as eagles and other vulture species, that perch on
electricity poles and towers) in a large part of the Easter Cape, and no doubt elsewhere in South Africa. In
order to reduce or completely remove this threat to these birds, it is recommended that, and as a matter of
urgency, all existing ‘unsafe’ powerline structures are identified and mitigated through the Eskom Species
Action Plan, and that all new transmission and distribution networks comprise only ‘safe’ infrastructure.
This would complement current initiatives by government and non-government conservation agencies aimed
at reducing the mortality of Cape Vultures from, notably, … poisoning, and drowning.
Wildlife WATTch Nov. 2011
…probably we could substitute ‘large eagles’ for ‘vultures’ in Australia, but apart from the food-supply
(large ungulate carrion) aspect for obligatory scavengers, which we can safely ignore (and the traditional
hunting aspect in Indonesia/Melanesia), do we even know how many of the above threats apply to our
raptors? Other items in Wildlife WATTch reveal that the South Africans are way ahead of us in matters of
e.g. raptor interactions with electricity and wind-power infrastructure. More follows… (Ed.)
…The World Bank (African Development Indicators) estimates that less than 5% of sub-Saharan Africans
have access to reliable electricity. It’s hardly surprising then that increasing the access of African people to
electricity has been recognised by most African leaders, forums and unions as being of top priority for the
continent. This political commitment is manifesting itself in numerous new powerline networks being
planned and built all over the continent. Electrification will require power generation and then distribution
of this electrical power to the end users, requiring thousands of km of overhead powerlines crossing our
continent. Whilst increased electrification of our continent is good news for people and economies, what
does it mean for our wildlife?
Journal of the Australasian Raptor Association
Boobook 31(2) July 2013
51
Experience in South Africa has shown that overhead powerlines are not always good news for the
environment through which they traverse. In South Africa, probably the most electrified African country to
date, the impact of electrical infrastructure on wildlife was first recognized during the 1970s and 1980s. Of
particular concern are our birds, many of which are vulnerable to collision with the overhead cables whilst
flying, or electrocution by live hardware whilst perching on poles. In addition to these direct impacts,
indirect impacts such as disturbance and habitat destruction also occur during the construction of powerlines.
Experience has shown that the birds most heavily impacted on by powerlines include… eagles, cranes,
storks, and many others. For many of these species, overhead powerlines are the biggest single threat to the
survival of their wild populations. Since most of the above bird families occur throughout Africa, it seems
reasonable to expect similar impacts to those now well understood in South Africa. If we are to ensure that
the electrification of Africa takes place in as bird-friendly a manner as possible, we need to act now through
building within-country capacity in the field of wildlife–powerline interaction, and influencing planning
processes.
…[The 13th Pan-African Ornithological Conference] once again highlighted the need to urgently address the
emerging powerline and wind-energy impacts, in an effort to curb the decline in the range and population
size of the eleven vulture species that inhabit the African continent…
Wildlife WATTch Feb. 2013
…again, read ‘eagles’ for ‘vultures’ in the Australasian context, and how much of this applies to developing
countries in our region, i.e. Wallacea/Melanesia, and should Australian expertise be helping with proactive
mitigation? (Ed.)
Natural death of Verreaux’s Eagle chick
The Vodacom mast at Philipstown, Northern Cape, South Africa was visited on 31 August with the purpose
to ring the Verreaux’s Eagle Aquila verreauxii chick in the nest on the mast. The chick was about 3–4 weeks
old, with the first feathers in pin. On our arrival at the nest, we found that the chick was dead. As there were
bare patches on the back of the chick, our first thoughts were that crows had attacked and killed the chick.
The carcass was collected and… [autopsied]. The top jaw-bone of a small predator was found inside the
beak of the chick. The bone may have been from a mongoose or a Cape Polecat. The fangs stuck in the
palate of the eagle chick and the bone could not move in or out. The chick probably starved to death,
because it was unable to get rid of the bone.
Wildlife WATTch Nov. 2011
…I wonder how often this happens here, especially now that Wedge-tailed Eagles eat foxes and feral cats as
well as the usual native and exotic herbivorous mammals. (Ed.)
Urban kestrels are stressed by human activity
American Kestrels, often seen perched along roadways, are abundant in urban and agricultural areas. Shorter
grass makes insects, snakes, mice and other prey more visible, and signposts, fences and telephone poles
provide excellent perches. However, a new study [Strasser & Heath 2013, J. Applied Ecology in press]
shows that even species considered ‘tolerant’ of human activity may be adversely impacted by human
disturbance; Kestrels nesting in close proximity to roads and developed areas had elevated stress hormones
and high rates of nest abandonment. The apparently favorable location, then, becomes an ecological trap.
Strasser & Heath conducted research along a major expressway, Interstate 84, and in suburban and rural
areas south of the state’s capital city of Boise. Since 1987, researchers have monitored nest boxes located
along the area’s roadways, in people’s back yards, and in sagebrush-steppe habitat. In this study, Strasser &
Heath were interested in understanding how human-dominated landscapes affect breeding Kestrels, with
particular attention paid to the link between disturbance, stress and nest failure. The two monitored the
boxes to determine nest fate, and collected a small blood sample from adult birds. The researchers were
Journal of the Australasian Raptor Association
52
Boobook 31(2) July 2013
looking at corticosterone levels, which indicate stress levels (the equivalent in humans is cortisol).
Corticosterone can lead to behavioural and physiological changes that allow individuals to cope with
stressful situations, while suppressing other activities such as reproduction.
The data showed that female Kestrels nesting in areas with high human activity, such as along noisy
roadways, have higher corticosterone levels, but males do not. This could be because females spend more
time in the nest box and thus are exposed more often to stressors such as vehicle noise. Too much ambient
noise may make it difficult for them to assess the level of danger, leading to higher stress levels and
increased vigilance behaviour, decreased parental care or the decision to abandon their nest. Kestrels nesting
in high disturbance areas were almost 10 times more likely to abandon their nest than those in more isolated
areas, and this effect lessened the further a nest was from the road. ‘We hypothesized that this was a
mechanism for how humans are impacting wildlife’, Heath said. ‘To birds, areas with human activity may
be perceived as a high-risk environment.’
Given that the vast majority of land in the continental United States is within a mile of a road, wildlife
increasingly are exposed to chronic levels of road noise. The resulting increase in stress levels could cause
fundamental changes in physiology and behaviour across species inhabiting human-dominated environments,
which over time could lead to population declines. As scientists continue to connect the dots between human
disturbances and the resulting long-term effects on wildlife, changes already are yielding positive results.
Research conducted in preserve areas, such as state parks, has led to reduced speeds and attempts to limit
noise, although noise mitigation, while locally effective, may not protect widespread populations such as
Kestrels from the pervasive threat of traffic noise.
The study concludes that until regulations or economic incentives are developed to encourage engineering
innovations that result in quieter roads, projects in areas of human activity with favourable habitat should be
discouraged, to decrease the risk of ecological traps. In the meantime, the nest boxes have been moved from
freeway locations to more suitable areas. ‘Birds evolved in an environment that was not dominated by
humans’, Heath noted. ‘In recent history, human roads and structures have left few areas untouched. We’re
just starting to understand the real consequences.’
www.sciencedaily.com/releases/2013/05/130510102025.htm
(per Greg Clancy, via Laurie Knight to Birding-Aus 16.05.2013)
..lessons for Australia, although we don’t install many kestrel nest-boxes here. (Ed.)
Journal of the Australasian Raptor Association
INTERESTING WEBSITES
At Nick Mooney’s suggestion, readers are invited to nominate raptor websites, YouTube clips etc. that
others might like to view. From David Whelan:
http://www.youtube.com/embed/2CFckjfP-1E
Northern Goshawk flies through tiny spaces at speed, in slow motion
Other sites/URLs welcome, for mention here in future issues.
Disclaimer: the views expressed in this journal do not necessarily reflect those of the ARA or BirdLife
Australia.
CONTENTS: BOOBOOK 31(2) 2013
From the President
Editorial
Reports and News:
25
26
BirdLife Australia EagleCAM at Sydney Olympic Park
New owl species for Wallacea
Victorian Area Rep’s report for 2013
Eagle nest issues in Tasmania
Grey Falcon vocalisation study
Accipiter genetic study
Black Falcon listing in NSW
27
27
28
28
29
29
29
Do Australian Peregrines parent differently?
Sooty Owl taxonomy
More on Tasmanian Boobook migration
Was there clutch-size depletion in Wedge-tailed Eagles after myxo?
Do Australian Barn Owls nest in barns?
Zygodactyl toe arrangement in raptors
30
32
32
33
36
36
The Powerful Owls of Springfield
Square-tailed Kites’ response to fire
38
38
Square-tailed Kite taking wasp nest
Square-tailed Kite juvenile
Black Falcons hunting
Little Eagle attempts to catch Glossy Black-Cockatoo
Black Falcon attacking Starlings
Black Falcon hunting Galahs
Black Falcon attacking Black-shouldered Kite
Small falcons and dragonflies
Brown Goshawk and Brown Falcon scavenging
Grey Falcon prey records
Nest defence by Black-breasted Buzzards
Black Falcon associating with Spotted Harrier
39
39
40
40
40
40
41
41
41
42
42
42
Book review
Journals
Conference abstracts
43
44
47
Powerlines contributing to demise of vultures in South Africa
Natural death of Verreaux’s Eagle chick
Urban kestrels stressed by human activity
50
51
51
Raptor File:
Articles:
Field Notes:
Literature:
International news: