AFRICAN PENGUIN
CHICK BOLSTERING PROJECT
Annual Report 2012: Attachment of Remote Sensing Technology to post-fledging
African Penguins
Richard B Sherley (Animal Demography Unit, University of Cape Town)
Summary:
Six PTTs were deployed in 2012, three on hand-reared (HR) chicks and three on naturally-reared
(NR) chicks. Location data were received for a mean of 68 days. In 2011, the five birds tracked
travelled to a mean maximum distance of 1023 km from their points of release, while in 2012, the
birds only travelled a mean of 734 km from their release sites. In 2011, three of the five birds
were tracked up to central Namibia, while in 2012 only one bird went further north than Lüderitz.
The raw tracks for 2012 suggest that the area south of Hondeklip Bay was once again important,
along with St. Helena Bay (not used in 2011) and the area around the Orange River mouth.
Neither the maximum distance nor the tracking duration differed significantly between the three
NR chicks and the eight HR chicks tracked so far. Neither mass at release, body condition index
at release or head length at release were correlated with either the maximum distance travelled
or the tracking duration for the 11 chicks tracked so far, suggesting that both HR and NR chicks
are capable of carrying PTTs. However, the percentage of fledglings tracked past 40 days
suggests that device induced early mortality cannot be ruled out.
Field Period:
June to October 2012
Objectives:
Continue to assess the feasibility and impact of deploying remote sensing technology on fledgling
African Penguins.
Continue to characterise the foraging areas that are important to post-fledging African Penguins
in the first few months after fledging.
Tracking methods:
In 2011, deployments were made on chicks which had been (partially) hand-reared by
SANCCOB in an effort to limit the risk of a negative outcome being induced by the PTT (see 2
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Ethical Considerations in the Project Proposal). In 2012, both partially hand-reared (3) and
naturally-reared (3) chicks were used. All hand-reared chicks had been removed from breeding
colonies when partially-grown because they had been abandoned by their parents or were
severely unlikely to fledge (based on body condition index scores, see Waller 2011). The handreared chicks for deployment were selected on an individual basis by SANCCOB Veterinarian, Dr
N.J. Parsons. Selection was based on the chick meeting all of SANCCOB’s standard release
criteria. The naturally-reared chicks were selected by Dr R.B. Sherley in the field. Selection was
based on their body condition index, mass and visual assessment of size. At the time of
deployment, each chick had a mass and head length measurement taken to ensure that they
were in good body condition (relative to a sample of wild birds from Robben Island in 2004; see
Waller 2011).
Five PTTs were deployed during 2011 and six during 2012. Each device was attached following a
slight modification of the method in Wilson et al. (1997). See Figure 1, Sherley and Underhill
(2011) and Sherley et al. (In prep) for more details.
Figure 1: The PTT is attached to the feathers on the back using tape and glue. First the feathers are lifted
and tape is attached to the underside sticky side up, a small amount of super glue is spread on the feathers
above the tape, the device is glued to the feathers and finally the tape is wrapped around the feathers to
make a neat and secure package.
In 2012, PTTs 119178, 119179 and 119180 were attached by Dr K. Ludynia and Dr R.B. Sherley
on 11 June 2012 to three naturally-reared fledglings at Robben Island (Table 1). These birds
were removed from their nest sites as blues (no down remaining), having been observed as blues
the week before (by K.J. Robinson), marked with Porcimark® and taken to the DEA research
house on the island. Here the devices were attached, they were kept in boxes overnight and
released the following morning. The aim was to release the fledglings at a commonly used
departure point on the shore so they would hopefully go straight out to sea.
PTTs 119181, 119182 and 119183 were attached by B M Dyer on 17 July 2012 to three handreared chicks at SANCCOB (Table 1). They were released from a boat offshore of Robben Island
on 19 July 2012, having spent two days at SANCCOB. The chicks were allowed to swim in a pool
within c. 10 minutes of the procedure being completed, so that their initial responses to the device
could be observed. Each of these three birds was allowed to swim with the device attached for c.
1 hour on at least two days before it was released.
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The duty cycle of the PTTs was set up to transmit every 45 seconds from 01h00 to 05h00 GMT
for every day in June, July and August and every other day after that.
Results:
General comparisons with 2011:
Location data were received for a mean (± SD) of 62 ± 41 days in 2011 and for a mean of 68 ± 30
days in 2012 (Table 1). The minimum times over which transmissions were received were 10
days in 2011 (PTT 105339) and 27 days in 2012 (119183). The maximum times were 98 days in
both years (105336 and 119178 respectively). In 2011, the five birds travelled to a mean (± SD)
maximum distance of 1023.2 ± 549.9 km from their points of release, while in 2012, the birds only
travelled a mean of 733.7 ± 352.6 km from their release sites (Table 1) although this difference
was not significant (t9 = −1.06, p = 0.32). The distances travelled have yet to be calculated for the
2012 deployments as we have yet to filter the data for erroneous or low precision fixes.
In 2011, three of the five birds were tracked up to central Namibia (Figure 2), while in 2012 only
one bird went further north than Lüderitz (although three others crossed into Namibian waters,
Figure 3). The remaining birds travelled on to South Africa’s west coast and apparently foraged in
St. Helena Bay and northwards to just north of the Orange River mouth (Figure 4).
So far, all 11 birds tracked have moved predominately in a clock-wise direction around the coast,
including the two released at Betty’s Bay (105338 and 105339) in 2011. This could indicate
genetic control of dispersal and the fact that birds forage on the West Coast, where food may be
limited (e.g. Gremillet et al. 2008) suggests minimal capacity for individual adaptation to local
habitat degradation.
Kernel density analysis conducted on the tracking data from 2011 suggested two key foraging
areas in regions of high and reliable primary productivity, one south of Swakopmund, Namibia,
and one north of Lambert’s Bay, South Africa (Sherley et al. In prep). Similar analysis has yet to
be carried out for the 2012 data as transmissions from the last active PTT only ceased on 06
October 2012. However, the raw tracks suggest that the area south of Hondeklip Bay was once
again important, along with St. Helena Bay (not used at all in 2011, Figure 2) and the area around
the Orange River mouth (Figure 4). The PTT on the bird that travelled to central Namibia
(119182) unfortunately only transmitted for 36 days (Table 1) and not much in the way of
apparent foraging was observed, although the raw positions suggest that this bird may have used
the area around Hondeklip Bay (South Africa) and Conception Bay (Namibia) as brief stopping
points.
Interestingly, Department of Agriculture, Forestry and Fisheries (DAFF) reported recently that the
2011 winter was relatively poor for small pelagic fish recruitment and there were apparently very
few young sardine and anchovy found during the annual survey conducted in May between the
Orange River Mouth and Cape Infanta. This roughly corresponded to the period during which
birds 105335, 105336 and 105337 were tracked moving to central Namibia. In contrast, the
survey of the adult fish conducted by DAFF in November 2011, revealed the presence of some
adult sardine between Lambert’s Bay and Hondeklip Bay, around where the bird carrying 105338
spent most of its time (Figure 2). This could indicate two strategies for dispersal (or a two-step
strategy) in which birds disperse onto South Africa’s West Coast to search the areas of reliable,
high primary productivity (see e.g. Hutchings et al. 2009) and only continue past the Luderitz
upwelling cell to the other area of high primary productivity south of Swakopmund if they fail to
initially find food in South Africa. However, this idea remains to be tested fully.
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Table 1: Summary of masses, tracking dates and distances travelled for fledgling African
penguins tracked with satellite transmitters. Maximum distance is the great circle route distance
between the release location and the transmission most distant from the origin. Distance travelled
is the cumulative distance covered between all validated locations. HR = (partially) hand-reared,
NR = naturally-reared (wild).
Year
PTT ID
Status
code
Mass at
release
(kg)
Release
date
Last
transmission
Maximum
distance (km)
Distance
travelled
(km)
2011
105335
HR
3.22
26 Jun 2011
23 Jul 2011
27
1466
1571
2011
105336
HR
3.18
19 Jul 2011
25 Oct 2011
98
1461
2258
2011
105337
HR
3.04
26 Jul 2011
25 Oct 2011
91
1334
2291
2011
105338
HR
2.95
13 Sep 2011
06 Dec 2011
84
516
1628
2011
105339
HR
3.20
13 Sep 2011
23 Sep 2011
10
339
446
2012
119178
NR
3.13
12 Jun 2012
18 Sep 2012
98
639
–
2012
119179
NR
3.02
12 Jun 2012
16 Sep 2012
96
359
–
2012
119180
NR
3.29
12 Jun 2012
24 Aug 2012
73
723
–
2012
119181
HR
3.10
19 July 2012
06 Oct 2012
79
646
–
2012
119182
HR
3.25
19 July 2012
24 Aug 2012
36
1407
–
2012
119183
HR
3.15
19 July 2012
15 Aug 2012
27
628
–
Days at
sea
Full descriptions of the results from tracking in 2011 are available in Sherley and Underhill (2011)
and Sherley et al. (In prep).
Hand-reared vs naturally-reared fledglings:
The three hand-reared (HR) chicks in 2012 travelled a mean (± SD) of 893.7 ± 444.7 km, while
the three naturally-reared (NR) chicks only travelled a mean of 573.7 ± 190.6 km, but this
difference was mainly as a result of the one hand-reared birds which travelled to Namibia. In fact,
comparing the duration over which the birds were tracked, the three naturally-reared birds were
tracked for a mean of 89.0 ± 13.9 days, as compared to the 47.3 ± 27.8 days for the three handreared chicks in 2012 and the mean of 56.5 ± 34.8 days for all eight hand-reared chicks tracked
so far (2011 and 2012). Neither the maximum distance (t9 = −1.34, p = 0.21) nor the tracking
duration (t9 = 1.53, p = 0.16) differed significantly between the three NR chicks and the eight HR
chicks.
Equally, there were no apparent differences in the tracks of the two groups in 2012 (Figure 5).
Given that the mean (± SD) release weights (NR = 3147 ± 135 g; HR = 3166 ± 76 g) and body
condition indices (NR = 0.63 ± 0.09; HR = 0.53 ± 0.17) of the two groups (in 2012) were broadly
similar and (unsurprisingly) did not differ significantly (release weights: t 4 = −0.22, p = 0.84; body
condition: t4 = 0.93, p = 0.40), this suggests that the naturally-reared chicks were not
disproportionately impacted by carrying the PTTs.
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Possible deleterious effects of tracking:
One of the main purposes of Phase 1 of this project was to determine if fledgling African
Penguins could cope with carrying PTTs for extended periods, whether the hand-reared and
naturally-reared chicks show similar behaviours and whether the latter group appear to be
capable of carrying PTT without any obvious deleterious consequences.
The section above seems to suggest that the two groups (NR vs HR) show no differences, but it
is worth considering that, overall, four birds were tracked for less than 40 days and all of the 11
birds were tracked for less than 100 days, thus it is worth considering potential deleterious
effects.
If the tracking duration and maximum distance are considered for all 11 birds, mass at release,
body condition index at release, head length at release, release date or person attaching the
device were all not correlated with either the maximum distance travelled or the tracking duration
(all p-values > 0.05). Release type (Boat vs Colony) appeared to affect the maximum distance
travelled (t9 = −3.29, p = 0.009) but not the tracking duration (t9 = 0.60, p = 0.56), with the six birds
released from a boat travelling a mean of 1157 ± 406 km versus 515 ± 169 km for the five birds
released at colonies. Why this might be so is not immediately apparent, except that four of the six
birds released from boats were tracked to central Namibia.
If we compare the mean tracking duration of 65 ± 33 days from the 11 fledgling African Penguins
tracked with results from the three other studies (of which the author is aware) that have tracked
fledgling penguins (also using PTTs), the mean tracking duration differed between studies (F(3,46)
= 3.26, p = 0.03), but the value from this report only differed from the mean duration obtained by
Wienecke et al. (2010) from 17 Emperor Penguins Aptenodytes forsteri (Table 2; Tukey’s HSD pvalue = 0.049) and the overall means for the species (Emperor = 93 ± 54 days, Adélie = 91 ± 41
days) did not differ significantly (F(2,47) = 1.37, p = 0.27).
However, mean first year survival has been estimated at 0.43 (Crawford et al. 2006) and 0.40 for
Dassen and Robben Islands from 1987 to 1999 (Whittington 2002). If the lower value is used to
model linear and exponential mortality functions, such that survival is 0.40 at 365 days, survival
rates of average fledglings should be expected to lie between 90 and 93% at 40 days and
between 82 and 87% at 80 days. Based on the percentage of PTT transmitting beyond 40 days
(64%) and 80 days (45%), it is worth considering the possibility that the devices may be inducing
early mortality in some birds. Of course, this must also be considered in light of the attachment
methods and the mean tracking duration in other studies (Table 2) and it is possible that
alternative mortality functions (such as a logistic function, which would model decreasing
mortality over time) may be more realistic.
Table 2: The number of fledgling tracked and the mean ± SD tracking duration in this study compared to
three other studies in which fledgling Emperor and Adélie penguins were tracked with PTTs.
Mean ± SD tracking
Study
Species
No fledglings tracked
Wienecke et al. 2010
Emperor Penguin
17
113 ± 56
Kooyman and Ponganis 2008
Emperor Penguin
15
71 ± 43
Clarke et al. 2003
Adélie Penguin
7
91 ±41
This report
African Penguin
11
65 ± 33
duration (days)
Page 5 of 11
Problems faced and future recommendations:
Given the relatively short deployment durations achieved so far, it is suggested that a duty cycle
from 01h00 to 05h00 GMT, every day for the duration of the battery life be used next year. With
this duty-cycle, it should be possible to track the birds for at least 100 days and a substantial cost
saving (c. R2000) can be made on each device as a supercapacitor is not require when the
device switches on every day.
In 2011, we noted that the antenna on the Kiwisat PTTs acquired from Sirtrack was longer than
anticipated, meaning that the placement of the device could not be as far aft on the birds as
would normally be preferred (Sherley and Underhill 2011). We discussed the possibility of a
shorter antenna with Sirtrack, but this possibility could not be entertained. Given that most of the
three birds equipped so far did not spend much time around the areas of human habitation (e.g.
Cape Town, Saldhana, Alexander Bay, Lüderitz, Walvis Bay) it seems unlikely that the current
generation of GPS-GSM devices will be able to guarantee data without a high risk of loss. We
therefore expect to continue using PTTs during Phase 2, pending discussions with scientists from
CapeNature and DEA.
Originally, the plan for Phase 2 was to deploy 20 devices, five on hand-reared chicks to be
released at Robben Island and five on naturally-reared chicks from each of Robben Island,
Boulders Beach and Stony Point. These colonies were selected because they had experienced
different population trends over the five years prior to 2011 (decreasing, stable, increasing
respectively) and because they were easy to access. However, after recent consultation with Dr
R.J.M. Crawford and Dr A.B. Makhado (Oceans and Coasts, DEA), it is clear that there is a desire
to equip fledglings from each of the seven major colonies (those with > 800 breeding pairs)
simultaneously. The plan currently is to deploy on five naturally-reared fledglings at each of
Dassen, Robben, St. Croix and Bird Islands and three naturally-reared fledglings at Dyer Island,
Stony Point and Boulders Beach (total 29) more or less simultaneously during next winter in
collaboration with DEA scientists and other scientists working at these colonies. Then, if further
devices could be sourced, it would be preferable to deploy an additional five on hand-reared
chicks (to be released on the West Coast) and five on chicks fledged during the summer breeding
peak at Dassen Island (R.J.M. Crawford, pers. comm.).
The Chick Bolstering Project partners have raised funds for 11 more PTTs during 2013 and these
will be added to 22 current available to DEA scientists to carry out the 29 deployments during
winter 2013 initially and (if the remaining six devices can be sourced) the 10 deployments later in
the year as per above.
Given the above, we are applying for the renewal of permit number RES2012/75, with an
allowance in the framework of this project for the deployment of up to 39 devices, under the
overall supervision and direction of DEA (e.g. Dr R.J.M. Crawford or Dr A.B. Makhado) and in
collaboration with management authorities at the relevant colonies, with colony specific limits
(see Table 3).
Revised project time-line:
October 2012:
1. Preliminary assessment of results from second set of deployments (in May to June).
2. Submission of a publication outlining results of pilot study (manuscript available on request).
3. Application for permits to carry out Phase 2 in winter 2013 and for renewed UCT AEC
clearance, based on findings from Phase 1.
Page 6 of 11
January 2013:
1. Latest date for submission of final report based on Phase 1 to DEA, CapeNature, UCT AEC.
2. Decision to be taken on whether it is necessary and prudent to continue to Phase 2 (in
consultation with DEA and CapeNature).
April to August 2013:
1. Deployment of up to 39 devices (PTTs) in collaboration with DEA scientists during for Phase
2.
February 2014:
1. Anticipated date of submission of final project report to DEA, CapeNature and UCT AEC.
June 2014:
1. Latest likely date of submission of manuscripts for publication of results from Phase 2.
Table 3: Proposed breakdown by colony of the 39 PTT deployments on fledgling African penguins planned
for 2013 and the relevant managing and permitting authorities.
Colony
No. of deployments
Local managing authority
Permitting authority
Dassen Island (W.C.)
10
(5 summer, 5 winter)
CapeNature
CapeNature
Robben Island (W.C.)
5
Robben Island Museum
DEA
Boulders Beach (W.C.)
3
SAN Parks
SAN Parks
Stony Point (W.C.)
3
CapeNature
CapeNature
Dyer Island (W.C.)
3
CapeNature
CapeNature
St. Croix Island (E.C.)
5
SAN Parks
SAN Parks
Bird Island (E.C.)
5
SAN Parks
SAN Parks
Hand-reared chicks
5
N.A. dependent on release
site
DEA
Total
39
Page 7 of 11
Acknowledgements:
These deployments were approved by the Animal Experimentation Committee at the University of Cape
Town (UCT), CapeNature and the Department of Environmental Affairs (DEA) as part of the Chick
Bolstering Project (CBP). The CBP is a collaboration between SANCCOB, the Bristol Conservation and
Science Foundation, the Animal Demography Unit (UCT), DEA (Oceans and Coasts), CapeNature,
Robben Island Museum and the International Fund for Animal Welfare.
Supporters of the Chick Bolstering Project, without whose aid the project could not go forward include:
Cheyenne Mountain Zoo; Basel Zoo; SeaWorld Busch Garden Conservation Fund and the SeaWorld
Animal Crisis Fund; Sea Research Foundation (Mystic Aquarium); Wallace Global Fund; Jenkinson’s
Aquarium; National Aviary; Disney Rapid Relief Fund; Zoo Leipzig; Living Coasts; Erlebnis Zoo Hannover,
Dierenpark Amersfoort; Le Pal Nature Foundation; Allwetterzoo Muenster; ZOOM Torino; La Palmyre Zoo;
Burgers Zoo; Georgia Aquarium; Leiden Conservation Foundation; Little Rock Zoo; Memphis Zoo;
California Academy of Science; Toledo Zoo; Fort Wayne Kid’s Zoo; Minnesota Zoo; Natura Artis Magistra;
Columbus Zoo & Aquarium; AZA Penguin TAG; Oceana; US Fish & Wildlife Service; Monterey Bay
Aquarium; SASIX; and Banham Zoo .
Mike Meyer, Rob Crawford and Bruce Dyer (Oceans and Coasts, DEA) are thanked for overseeing the
logistics of setting up the devices on an Argos account and downloading the data in 2011. Bruce Dyer is
also thanked for his assistance with the deployment of the devices. The staff and volunteers at SANCCOB,
but particularly Dr Nola Parsons, Venessa Strauss, Margaret Roestorf and Nicky Stander, are thanked for
their tireless efforts to rear the chicks and arranging the logistics that went into releasing them. Lauren
Waller and Deon Geldenhuys (CapeNature) are thanked for assisting with the logistics the planned release
at Stony Point. I thank J-P Roux (Ministry of Fisheries and Marine Resources, Namibia) for providing
additional information.
Page 8 of 11
Figure 2: The west coast of Southern Africa and the full paths of the five chicks carrying PTTs released in
2011. 105335 (red) had covered about 1600 km and stopped transmitting on 23 July 2011, after 27 days at
sea. 105336 (green) and 105337 (yellow) covered just over 2000 km each and stopped transmitting on 25
October 2011 after 98 and 91 days at sea respectively. PTT 105338 (blue) transmitted for 84 days (13
September to 6 December), in which time the bird carrying it covered c. 2000 km. PTT 105339 (pink) only
transmitted for a total of 10 days at sea.
Figure 3: The west coast of Namibia and the paths (in red) of the three fledglings carrying PTTs released
in 2011 and the path (in green) of the one fledgling carrying a PTT released in 2012 which went north of
Lüderitz.
Page 9 of 11
Figure 4: The west coast of South Africa and the portions of the paths of the fledglings carrying PTTs
released in 2011 (in red) and 2012 (in green) south of Lüderitz.
Figure 5: The west coast of South Africa and the individual tracks of the five fledglings carrying PTTs
released in 2011 that remained south of Lüderitz. PTT 119178, 11979 and 119180 were naturally-reared
chicks and PTTs 119181, 119182 (yellow, final position in Namibia not shown) and 119183 were handreared chicks.
Page 10 of 11
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