2011 Annual Report of NWT Wildlife Research Permits and Western ...

Wildlife Species Research:
Birds
OBJECTIVES:
´ ´ To evaluate the latitudinal variation in life history
traits of yellow warblers;
´ ´ To test the generality of winter habitat impacts
on breeding success (“carry-over” effects)
in neotropical songbirds by studying a species
on the western flyway; and
´ ´ To determine whether there is a latitudinal impact
on carry-over effects. It is expected that carry-over
effects will be more pronounced for birds breeding
in more northerly locations.
METHODS:
Breeding activities were monitored and feathers sampled
at two locations in Canada: Revelstoke, BC and Inuvik,
NWT. Data from Revelstoke was collected by team
research technicians under the supervision of Dr. David
Green. Breeding activities (date of first egg, clutch size,
development periods, and number fledged) were
monitored throughout the season at each site. The
majority of all breeding adults were captured using mist
nets. Each bird had standard body metrics taken, six
feathers sampled–three greater covert (moulted on
wintering grounds), two primary coverts and a single
retrice (moulted on breeding grounds), and was colourbanded
for identification purposes. Nestlings were banded
at seven days of age.
RESULTS AND MAIN CONCLUSIONS:
The first male yellow warbler arrived on our study site
on 22 May. Males arrived over a 20 day period, with
the majority arriving near the end of May. Females
followed shortly thereafter. A total of 114 adults were
caught throughout the season and were sexed, aged,
measured and feather sampled. Of these, 90 adults were
new captures and were newly banded. The earliest nest
was initiated on May 26 and the last nest was predicted
to fledge on July 28. Over the course of the breeding
season we monitored 49 breeding pairs and located
a total of 77 nests, 61 of which turned active with eggs.
Average clutch size across all breeding attempts was
4.2 eggs, incubation periods spanned 11 days, and young
usually left nests after 9 days. Approximately 70% of
all breeding pairs successfully fledged young. Relative
to the Revelstoke population, males arrived later, nests
were initiated over a shorter time period and later in the
season, clutch sizes were larger, development periods
were similar and overall pair survival was higher in Inuvik.
Yellow warblers breeding at high latitudes appear to have
shifted some but not all life history traits towards
a “fast” life history. Stable isotope data from 2011
feather samples are currently being analyzed.
LONG-TERM PLANS .
AND RECOMMENDATIONS:
This was the final year of a three year study of breeding
ecology of yellow warblers in Inuvik, NWT (2009-2011).
We plan to return during the 2012 season to resight
banded individuals from previous breeding seasons.
Band returns will allow for a better estimate of population
survivorship. The Inuvik study sites appear to be important
breeding sites for yellow warblers as they are high density,
productive breeding grounds.
COMMUNITY INVOLVEMENT:
On 7 June 2011, we presented our research to students
enrolled in the Environment and Natural Resources
Technology Program at Aurora College, and invited
students to participate in our research. On 14 July 2011,
we provided a public presentation of our research
proposal, methods and preliminary findings at the Aurora
Research Institute. Throughout the season, we stayed in
contact with the Gwich’in Renewable Resources Council
and offered to take on students to provide experience
with bird i.d., nest monitoring and bird banding.
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