Weekly Reports

On October 3, the Lesser Slave Lake Bird Observatory concluded our Fall Songbird Migration Monitoring program for 2025; our 31^st year of standardized efforts. Although the trees still bear their yellowed leaves, very few migratory bird species remain in our forests as the stillness of winter tightens its grip. For the third year in a row, Fall finished without a single net-hour lost to sub-zero temperatures. Since birds can get chilled in the nets, we only open them above 0 °C. Historically, Fall has wrapped up late September when cold early morning temperatures keep the nets closed and monitoring using mist-nets becomes impractical.

Within seven hours daily between July 12 to October 3 we encountered 63,000 birds from 153 species. Although observations were diverse and well above the Fall average of 126 species per fall, there were no new species. The highlight was the first Black-backed Woodpecker since 2021 and just the thirteenth we have encountered at our station since trials in 1993. Black-backed Woodpeckers are among the first to recolonize the habitat left by forest fires. Their black backs help them camouflage on burnt trees. However, the size and severity of forest fires is increasing with climate change and studies suggest large burns cannot be used by this post-fire specialist either.

Overall, this Fall was late. Canada Warblers were heard singing weeks after they normally quiet down. Many warbler species were encountered mid-September when we often see the last of them late August to the first week of September. Mid-September also saw late broods of thrush, sparrows, and some warblers within weeks of their fledging – something I’m not sure I’ve seen so late before.

Despite the weather being exceptionally warm and calm, which should have been perfect for capturing birds, we had the odd Black Bear haunt our station and a Red Fox that would run right up to us likely expecting us to feed him. Since we often could not open our nets with these predators around, Fall 2025 captures were just above average to become the thirteenth busiest of our 31 years. In total, we banded a preliminary 2,491 birds from 63 species.

No species saw record low captures, but Blue-headed Vireos broke their previous record of eight banded in fall 1995 with 10 banded, and Bay-breasted Warblers set the bar high charging past their previous record of 50 banded in 2012 with 69 banded this fall. Capture highlights included three Pileated Woodpeckers (our 13^th,14^th, and 15^th of fall monitoring), two Blackburnian Warblers (our 5^th and 6^th), and one Gray Catbird (our 4^th).

With three weeks of Owl Banding left, it is already the fourth busiest owl season since we began monitoring in 2004 with 180 Northern Saw-whet Owls banded. We are close to beating 2018’s 189 owls, and even 2006’s 201 owls, but still have some work to do if we hope to surpass 2021’s 214 owls.

Since we only have Owl Banding to finish, this is our final article of 2025. Thanks for reading and ‘see’ you next year!

By Robyn Perkins, LSLBO Bander-in-Charge

All species banded during Fall Migration Monitoring 2025 in order of frequency: