Posted | filed under Weekly Reports.

Southward songbird migration is well underway at the Lesser Slave Lake Bird Observatory. Though the sky is relatively quiet, the nets are getting busier such that July 27 captured 141 birds to become the busiest day of captures so far this fall monitoring period.

Since migration began, the nets have been busier than average overall, albeit slower than the record smashing conditions of last year. Our season banding total is now at 1,017 bands from 39 species. Within this season’s top five most banded species there is a wide gap between Swainson’s Thrush in fifth place with 56 banded and Myrtle Warblers in fourth place with 102 banded. In third place is Tennessee Warblers with 108 banded – a far cry from last year’s 1,174 record high.

Above: This American Redstart banded this week is fairly representative of what most of the Redstarts we have been banding look like.

The second most frequently banded species so far this fall has experienced wild fluctuations in captures since yearly monitoring began in 1994. At 141 banded, American Redstarts have not yet surpassed their fall average of 226 banded per season and are well below their record of 609 banded in 1998. They have, however, already surpassed their record low of a measly 57 banded in 2012. 

American Redstarts can startle their insect prey out of the understory by quickly flashing their tails and wings. Since they then jump up to catch these insects on-the-wing, they have a wider bill than most warbler species. Females and young redstarts are gray and yellow with the males becoming a brilliant black and orange shortly after their first birthday. This is another oddity for warblers which typically get their bright colours in the spring and fade back in the fall rather than becoming flashy year-round after their first breeding season. These older males are scrappy and will sometimes simultaneously maintain two territories with two different mates.

Above: This Yellow Warbler is already finding its way south without the help of its parents despite being only two months old.

Our top banded species so far, the Yellow Warbler, has already surpassed both their previous low of 27 banded in 2014 and their average of 129 banded per fall. In fact, at 204 banded, they are edging closer to their previous record high of 291 banded in 2020. Having up to 35 different subspecies allows the Yellow Warbler to be one of the most numerous warblers in all of North America. They can be found almost anywhere south of the Tundra in Canada and the United States. They even have subspecies in Mexico and Central America which do not migrate at all. In spite of this wide range, small, but steady declines have added up to an approximately 20% decrease in Yellow Warbler populations since 1966.

If you would like to try your luck at seeing any of these species up close during our monitoring, we are again offering tours every Wednesday and Saturday through the month of August. Contact the Boreal Centre for Bird Conservation at (780) 849-8240 for more information. 

By Robyn Perkins, LSLBO Bander-in-Charge