Manitoba’s Nocturnal
Owl Survey 2001
Progress Report
Our Purpose and the Value of Your
Participation
Birds of prey, including the mysterious and
majestic owls, are high on the food chain and as
such are vulnerable to environmental change
brought on by our modern activities. These
changes can include toxins in their food supply,
absence of food and the absence of nesting and
hunting grounds, otherwise known as habitat loss.
This survey seeks to provide sound information on
owl distribution, habitat use, abundance and
population trends. This will lay the groundwork for
the development of sound conservation strategies
by identifying species in need and by providing a
tool for evaluating current management programs.
An equally important survey goal is to provide an
opportunity for people such as yourselves to get
involved through active participation. We could not
do all this without you!
flaps its pointed wings in deep, powerful,
falcon-like strokes.
Photo Credit: Jim Duncan
Patsy Duncan holding a recently banded Northern Hawk Owl
near South Junction Manitoba.
Manitoba Owls
Species Profile:
Northern Hawk Owl (Surnia ulula)
- by Jim and Patsy Duncan
0ne of the least-studied birds of North America,
the Northern Hawk Owl has a bold nature and
seems to lack fear of humans, delighting birders,
who often travel great distances to observe it. It
is atypical in morphology and behavior compared to
other northern hemisphere owls, resembling in
many ways the accipiter hawks - hence the name
Hawk Owl. Primarily diurnal, this species usually
perches atop prominent trees. When flying, it
either glides low over the ground at high speed or
The only species in its genus, the Northern
Hawk Owl breeds in the circumpolar boreal
forest zone from Alaska eastward through
Newfoundland, and from Scandinavia through
Siberia. It nests in dead tree stubs or
woodpecker holes, especially in open coniferous
or mixed coniferous, deciduous forests, burned
over areas, or muskeg. Although this owl winters
throughout its breeding range, it periodically
"invades" southern Canada and the northern
United States. The magnitude and extent of
these winter irruptions are thought to correlate
with high reproductive success followed by
severe winter conditions and decreased prey
availability. Early studies suggest that this owl
MANITOBA’S NOCTURNAL OWL SURVEY 1
eats primarily small rodents, but recent evidence
indicates that grouse, ptarmigan, and hares
comprise a greater proportion of their diet than
previously thought.
Photo Credit: Jim Duncan
All North American owls, except the Burrowing
Owl (Speotyto cunicularia), show appreciable
reversed sexual size dimorphism - the female is
larger than the male. However, this dimorphism is
not strongly pronounced in the Northern Hawk
Owl. Despite its lack of skeletal ear asymmetry, it
can locate and capture concealed prey up to 30 cm
under snow cover. While much remains to be
learned of the natural history of this species on
its breeding range, there is no evidence that this
species is at risk.
Charts
As most of you know, the survey protocol
changed significantly in the year 2000. Route
length, spacing between listening stations and
listening time all changed and as well, the
playback was dropped. The change was made in
order to standardize the methods across Canada
and become part of a nation-wide owl survey. As
such, the owl detection trends from the two
sampling periods are separated in the charts on
pages 3 and 4.
These charts show the number of each owl
species heard per kilometer surveyed during the
11-year survey period.
Where We Surveyed in 2001
In 2001, 57 routes were surveyed (slightly less
than the year before) and are displayed on the
map shown to the right. Routes at Spruce Siding
(near Richer), Fire Road 31 South (near
Hadashville), Glenboro-Stockton and Athapap Road
(near Cranberry Portage) have all been done 2 or
more times in 2001.
The map is divided into regions known as ‘Bird
Conservation Regions’ (BCR), accepted widely in
North America as the planning unit for bird
conservation studies.
The survey is getting better with increasing
representation in the western part of the
province. To get accurate representation of owl
populations throughout Manitoba we need more
volunteers in the north and west! If you can help
out, let us know! Every little bit helps!
MANITOBA’S NOCTURNAL OWL SURVEY 2
MANITOBA’S NOCTURNAL OWL SURVEY 3
Owl Detection Trends
0.14
0.12
# per Km
0.1
0.08
0.06
0.04
0.02
0
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
Year
GHOW
BOOW
NSOW
GGOW
GHOW Great Horned Owl; BOOW Boreal Owl; NSWO Northern Saw-whet Owl; GGOW Great Gray Owl
MANITOBA’S NOCTURNAL OWL SURVEY 5
O wl Detection T rends
0.045
0.04
0.035
# per Km
0.03
0.025
0.02
0.015
0.01
0.005
0
1991 1992 1993 1994 1995 1996 1997 1998 1999
2000 2001
Year
BARR
LEOW
EASO
NHOW
SEOW
BARR Barred Owl; LEOW Long-eared Owl; EASO Eastern Screech Owl; NHOW Northern Hawk Owl; SEOW
Short-eared Owl
MANITOBA’S NOCTURNAL OWL SURVEY 6
2001 Nocturnal Owl Survey
Estimated Distance from Stations to Owls Reported
Interesting Factoids 2001…
•
•
•
•
In 2001, 57 routes were surveyed by 91
volunteers, down slightly from 59 Routes in
2000. For every station surveyed, 0.27 owls
were heard which was up slightly up from 2000
when 0.24 were heard for every station
surveyed. This means that surveyors have a
greater than 25% chance of hearing an owl at
a station.
<100m
7%
100-500m
44%
For every 1 km surveyed, 0.17 owls were heard,
up from 2000 when 0.15 were heard for every
1 km surveyed. That equals one owl for every
5.88 km traveled during the survey.
Boreal Owls were the most commonly
encountered (54 on 14 routes) followed by
Great-Horned Owls (47 on 17 routes) and
Northern Saw-whet Owls (29 on 15 routes). At
least one owl was reported from 39 of the 57
routes surveyed.
Rudolf Koes and Reto Zach struck gold on
Route 4 (Bird River – PR 315) near Nopiming
National Park with 13 owls heard (all Boreal
Owls).
•
Donna Danyluk, Ian Ward, Francois and Dana
Blouin were fortunate as well surveying routes
1 (Powerview North) and 35 (314 – Nopiming Cat Lake) which were not far behind each
recording 10 owls.
•
Four Boreal Owls, five Northern Saw-whet
Owls and one Northern Hawk Owl were
recorded at Powerview despite problems with
traffic (thank you Donna and Ian for your
perseverance and patience), and 10 Boreal
Owls were recorded at Cat Lake.
•
distance not
recorded
3%
Route 131 (Vogar West), surveyed by Georgina
and Raymond Larson, was close behind with
nine owls reported (seven Great Horned Owls
and two Great Grey Owls).
>500m
46%
It is interesting to note that volunteers reported that 90%
of owls heard were from an estimated distance of more than
100 meters from each stop. Half of which were more than an
estimated 500 meters away! So keep your ears peeled!
The New Survey Protocol
In the year 2000 the protocol for Manitoba’s
Nocturnal Owl Survey was changed dramatically
in order to be part of the international standard
for monitoring owls in North America. By using
one common protocol across Canada and the
U.S., we will be better able to monitor owl
population trends across broad geographic areas,
similar to that done by the Breeding Bird
Survey.
Briefly, the major changes for 2000 were:
§ 2 minute silent listening period per station
with no tape playback;
§ 1.6 km spacing between stations;
§ routes in multiples of 10 stations each; and
§ random route locations.
MANITOBA’S NOCTURNAL OWL SURVEY 7
FAQs
Q Can I create my own route?
As tempting as it is to survey in an area where
owls are known to be abundant, if everyone did
this than we would not get an accurate picture of
the distribution and abundance of the different
species of owls in our province. Because this is a
scientific study and because we are attempting to
create a standard protocol across Canada one rule
we must conform to is that the routes be
randomly distributed. The good news is there is
some leeway in that you are given a choice
between three possible routes to survey. I
suspect that some of you may hear no owls at all.
Although your disappointment is understandable,
remember that even this data is valuable to the
understanding of the owls’ ecology. So take heart!
And keep up the good work.
Q Why are the listening stations spaced at 1.6
km (1 mile)?
We are adopting a standard spacing of 1.6 kms in
Canada for two main reasons; 1) this distance
reduces double counting of owls, and hence makes
more efficient use of your time; and 2) if we were
to use a playback at some point to target a certain
species, spacing of 1.6 km reduces the influence of
the playback on the next stop.
Q Can I reduce the space between stations to fit
more stations in a route?
We strongly recommend the minimum spacing of
1.6 km be maintained. If noise is a problem at a
particular station, it can be moved slightly (100 m).
However, so as not to alter the distance of the
full route, measure your subsequent station 1.6 km
from where this station was originally to be. The
important feature is that the locations remain
consistent from year to year, allowing for
significant long term monitoring.
Q Is it essential that my route have 10 stops?
Yes! Your route should have a minimum of 10
stops. The 10 stop route forms the basis for
population monitoring and is an essential part of
the study allowing for cross analysis of the data
collected between routes. If you so choose, you
can double your route to 20 stops, adding to the
pool of data and doubling your fun!
Q Why are there so many information sheets
to fill out?
There has been a significant increase in the
amount of forms to fill out. We are entering all
this information into our database to make
things easier in the future. Once you have filled
out the surveyor information (name, address,
etc.) you will not have to do so again, the same is
true for the survey route information. The route
description and map are essential should you
stop doing the survey and your route is passed
on to someone new.
More Bird Related Volunteer Opportunities in
Manitoba
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Breeding Bird Survey (BBS)
Migration Monitoring - Songbird Banding
Migration Monitoring - Hawk Watch
Christmas Bird Count (CBC)
Manitoba Conservation Data Centre
Prairie Nest Record Scheme
Project Feederwatch
Ferruginous Hawk Recovery Program
Bluebird Nest box Monitoring
Parkland Mews Falconry and Bird of Prey
Education Centre
Manitoba Wildlife Rehabilitation Centre
MANITOBA’S NOCTURNAL OWL SURVEY 8
For more information check out the following Web site
at Manitoba Conservation:
www.gov.mb.ca/natres/wildlife/managing/pif_volun
teers.html
Delta Marsh Birding Festival
May 10-12, 2002
The Delta Marsh Birding Festival is a 3-day event
for birders and bird lovers alike celebrating the
diversity and wonder of birds! Delta has unique
and wonderful birding opportunities with experts
in all aspects of birding life. We hope you can
join us for this celebration of bird life during the
peak of spring migration at Delta:
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shorebird and waterfowl identification
guided bird tours to various habitats
birding by ear
birding by canoe
visits to Sharptail Grouse dancing grounds
banquet with keynote speaker Jim Duncan
fish fry and silent auction
bird banding
Mother’s Day picnic
For more information call Russ Mead at
857-8637 or fax at 857-4683.
For information regarding conservation and
wildlife in Manitoba see:
www.gov.mb.ca/natres/wildlife/index.html
Owl Survey Participants in 2001
Cheryl Bailey, Jim Bell, Robert Berger, Francois
and Dana Blouin, Mark Bodnar, James Bradley,
Tim Byers, Dan Chranowski, Ward Christianson,
Jack Crolly, Carolyn Curtis, Cal Cuthbert, Donna
Danyluk, Buster Day, Jim, Patsy, Connor and
Brooke Duncan, Jim Fisher, Foster Fournie,
Maureen Frolick, Mike Gigian, Jeff Gowler,
Harry Harris, Heather Hinam, George Holland,
Wally Jansen, Louise Kernatz, Ken Kingdon,
Rudolf Koes, Bill Koonz, Michaela Kraft, Georgina
Larson, Raymond Larson, Patrice Letain, Matt
Loewen, Kurt Mazur, Alex McIlraith, Celia
McLaren, Don and Ardythe McMaster, Marilyn
Meyer, Al Mickey, Lorelie Mitchell, Wayne Neily,
Dayle Neufeld, Lory and Audrey Neufeld,
Jeremiah Niekamp, Laura Pearson, Morley
Pedwell, Charlotte Pedwell, Ray Pettinger, Barb
Pettinger, Leon Pewarchuk, Aimee Pittet, Ryan
Porteus, Bill Pruitt, David Raitt, Amelia Reid,
Monica Reid-Wrong, Don and Roxie Reimer, Vic
Reimer, Marlene Remple, Dave Roberts, Len
Ryzner, Tom Scott, Rosalie Sigurdson, Connie
Singleterry, Bob Smith, Isabelle Smith, Richard
Staniforth, Diana Staniworth, Peter Taylor, Ross
Teague, Lorna Teague, Lisa and Wes Tretiak,
Will Trowell, Joanne Tuckwell, Jeff Turner,
Lorraine Turner, Robyn and Todd Underwood,
Piet Van Dijken, Liis Veelma, Marlene Waldron,
Bill Walley, Ian Ward, Ted Wilson, Larry and
Judy Winslow, Margaret Yorke, Reto Zach and
all friends and family members we may have
missed.
Northern Saw-whet Owl
Thanks To All Participants
Thank you to all participants of the 2001 Owl
Survey veterans and new comers alike! We couldn’t
do this without you. Hats off to all those
participants who surveyed more than one route.
Your extra effort is greatly appreciated.
MANITOBA’S NOCTURNAL OWL SURVEY 9
Thank you for your help with Manitoba’s Nocturnal Owl Survey
and we hope you are looking forward to the 2002 survey!
Jim Duncan
Wildlife and Ecosystem Protection Branch, Manitoba Conservation
Box 24, 200 Saulteaux Crescent, Winnipeg, MB R3J 3W3
Ph: 204-945-7465
[email protected]
Manitoba’s Nocturnal Owl Survey is supported by:
MANITOBA’S NOCTURNAL OWL SURVEY 10
rsh Bird Observatory
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