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Osprey in the West Kootenay
| Introduction:
Objectives:
Osprey:
Study
Area:
The
Study:
Results:
Discussion:
Conclusion:
Acknowledgements:
Literature cited:
Prepared
by
Nelson
Naturalists:
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OSPREY
IN
THE
WEST
KOOTENAY:
Balfour
to Waneta
Funded
by the Royal British Columbia
Museum and Columbia Basin Trust
through Living Landscapes |
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Introduction:
The
Osprey (Pandion haliaetus)
is a highly visible and well-loved bird of the Kootenay. It has adapted well to living in close proximity to humans
and will nest readily and very successfully on artificial nest structures.
Their large twiggy nests and breeding habits are easy to
spot and observe, thus, the Osprey is an ideal candidate for monitoring
breeding success.
Because
Osprey are at the top of the food chain, monitoring the population
provides an indication of the health of their aquatic environment.
Successful rearing of their young tells us that their and
our environment is doing well.
The
purpose of our Osprey survey, made on behalf of Living Landscapes
by Nelson Naturalists, was to study the population and breeding
success of this important bird.
Objectives:
The
objectives of the study were to:
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submit
our data to the provincial bird database and the BC Nest Record
Scheme in Victoria, BC. |
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complete
the data compilation and produce a summary in the form of
an educational pamphlet to be distributed in the local community. |
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make
the educational pamphlet available to the local naturalist
clubs (Nelson Naturalists, West Kootenay Naturalists, Rocky
Mountain Naturalists and Arrow Lakes Naturalists), Kokanee
Creek Provincial Park Visitor Centre, Creston Valley Wildlife
Management Visitor Centre, Tourist Information Centres and
Selkirk College Wildland Recreation Department and local schools
in the Columbia Basin. |
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make
the results of our survey
available to the Living Landscapes World Wide Web site. |
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write
articles that highlight
the survey results in the local papers and the BC Naturalist,
the FBCN newsletter. |
Osprey:
Osprey,
also known as fish hawks, are found almost world-wide along coastlines,
lakes and rivers. Ospreys occur in tropical and temperate parts
of all continents, breeding from north-western Alaska and central
Canada south to Bahamas and Mexico (Campbell, 1990). They are a
migratory species and in the western hemisphere winter from southern
United States south to Chile and Argentina (Campbell, 1990). They
are the only member of the family Pandionidae.
The
Osprey is often seen flying, hovering and perched in trees beside
water courses. The
Osprey subsists almost entirely on fish, which they capture by spectacular
dives from the air. They plunge feet first and after a successful
strike, the bird rises heavily from the water and flies away, carrying
the fish head-forward in its talons.
They are the only raptor whose front talons can turn backward.
Osprey are easily recognized by their distinct markings;
dark brown above, white below, with a white head that has a prominent
dark eye stripe. Females
have a darker streaking around their neck and are usually larger
than the males. The juvenile plumage is fringed with pale buff above.
In flight, their long narrow wings are bent back at the wrist, dark
carpal patches conspicuous; wings slightly arched in soaring.
They are often spotted after hearing their distinct cry as
they glide overhead.
Study
Area:
The
survey was conducted along the water ways from Balfour to Trail
from the junction of the West Arm of Kootenay Lake, down the Kootenay
River to the confluence with the Columbia River in Castlegar and
down the Columbia River to Trail (including Waneta)
(Figure 1). |
Figure
1:
Study
area.
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The
biogeoclimatic zone for this area is in the ICHdw except for a small
area near the US border at Waneta which is ICHxw.
The Interior Cedar Hemlock dry, warm (ICHdw) is the most
diverse subzone in the province in terms of tree species.(Braumandl
et al. 1992). The most prominent feature of this subzone that contributes
to the Osprey success is the remaining tall tree snags left from
a long history of fire.
The
Study:
In
the spring of 1997, four members of the Nelson Naturalist Club were
approached by a well- known local birder and asked to survey and
monitor the local population of Osprey.
In the spring of 1998, we applied for and received partial
funding through Living Landscapes.
The
area is very large so was divided into two sections.
It was quickly discovered that even though the distance from
Nelson to Trail was greater the number of nests between Nelson and
Balfour was higher. Each
team drove their route, exploring side roads to find viewing advantages
for each nest. Information
from local people gave valuable information about location and history
of some of the nests. The
nests were monitored,
by viewing from a distance either using binoculars and/or a spotting
scope. The nests were
not disturbed in any way. Observations were made at least once a
month from late April to the beginning of September. At the end of the season nest record cards were filled
out for each nest with activity, and submitted to the BC Nest Record
Scheme in Victoria. Data
was collected in 1997, 1998 and 1999.
Results:
The
nest record cards have been submitted yearly to the BC Nest Record
Scheme. The following
table shows a brief summary of our findings.
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Results
of Osprey Survey
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1997
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1998
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1999
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Number
of occupied nests
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51
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99
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46
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Number
of productive nests
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33
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65
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26
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Percentage
of productive nests
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65%
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66%
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57%
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Number
of Osprey juveniles
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43
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96
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40
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Average
number of Osprey juveniles per productive nest
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1.3
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1.5
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1.5
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An
information pamphlet has been produced for distribution.
A copy is attached
Discussion:
We
originally started, in 1997, with four volunteers from the Nelson
Naturalists with the objective of submitting our data to the BC
Nest Record Scheme. The
additional objectives were added when funding from the Living Landscapes
became available in 1998.
The
British Columbia Nest Record Scheme was started in 1955 by graduate
students in the Department of Zoology at the University of British
Columbia (Campbell, R.W, 1997).
By compiling the data of numerous observers, the BC Nest
Record Scheme provides a provincial information resource for interpreting
the nesting success of Osprey and other bird species.
The area of our study has long been recognized as having
a large population of Osprey, several graduate students have done
their masters’ studies on the Osprey and it is hoped that continued
monitoring will contribute
to the database
and to the understanding of the diversity and health of this area.
The
Osprey nest on a large variety of structures such as pilings, bridges,
microwave towers, power poles, channel markers and trees.
The trees, either dead or alive, were not the location of
choice, although the birds seemed to be opportunistic and build
their nests as close to the water as possible on whatever was handy.
Many local residents take pride in providing poles and platforms
for their local favorites and most times are rewarded with a resident
pair. The determination
of some nesting pairs was steadfast as proven out by the pair that
stuck to their nest and raised their young 10 m from a major bridge
repair, with noisy equipment running, at Taghum,
just outside of Nelson in 1998.
Of
the three years monitoring 1998 had the highest number of occupied
nests and number of young - almost twice as many as in 1997 and
1999. In 1998, the
weather was drier in the crucial nesting period, as the spring and
early summer of 1997 and 1999 were cold and wet.
Surprisingly the percentage of productive nests and young
per nest did not vary greatly from year to year.
The numbers presented here are limited and additional years
of data will have to be viewed to interpret trends.
The
three years of monitoring added immensely to the observers’ knowledge
of these highly visible birds.
This in turn helped with note taking and interpreting the
birds’ various behaviors. As well, the effort to produce an educational
pamphlet has been, in itself educational.
We hope to continue with the monitoring in the coming years.
Conclusion:
The
results of three seasons of monitoring nests indicate an average
of 63% were productive. The average number of juveniles per productive
nest was 1.43. These
numbers are limited but show surprisingly very little variance from
year to year.
The
information pamphlet is completed and will be distributed.
This
report, the poster from the Living Landscapes conference at Fort
Steele in October, 1999 and the pamphlet will be on the Living Landscapes
website by the end of February, 2000.
Acknowledgements:
Nelson
Naturalists Club, Mike Panian (Ministry of Environment), David Smith
(BC Hydro), George Kosowlan (West Kootenay Power), Ian MacIntosh
(Spilker, Kew & MacIntosh), Robin Rohrmoser, Chris Rohrmoser,
Linda Van Damme, Ruth Beck, Nancie Dohan, Marlene Machmer, Susan
Wade, Larry Prosser, Gillian Cooper, West Kootenay Naturalists Club,
Wayne Campbell, and Gary Price (BC Parks)
And
of course, many thanks to the Living Landscapes Program for funding
support.
Literature
cited:
Braumandl,
T.F. and Curran, M.P., 1992. A Field Guide for Site Identification
and Interpretation for the Nelson Forest Region, Land Management
Handbook Number 20. BC
Ministry of Forests.
Campbell,
R.W., Dawe, N.K., McTaggart-Cowan, I., Copper, J.M., Kaiser, G.W.,
McNall, M.C.E., 1990, The Birds of British Columbia, Volume Two,
Nonpasserines, Diurnal Birds of Prey through Woodpeckers.
Campbell,
R.W., 1997, British Columbia Nest Record Scheme, Instruction Manual.
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