28 September 2024

As I mentioned in Meet the Baypoll, I visited Bird Lab’s Hays Woods banding station on Tuesday where I had up close looks at warblers and thrushes. Stars of the show were a bay-breasted warbler and a blackpoll captured in the same mist net. I got good photos of the bay-breasted warbler (Setophaga castanea) both front and back. I think he’s more confusing from the back.

Here he is with his blackpoll buddy.

Tuesday was a big day for Tennessee warblers (Leiothlypis peregrina). At least six were banded while I was there. They are hard to identify in autumn because so many of them are unremarkable immature birds without the classic dark olive back and gray head of breeding males. For example …

… and another example, though this one has a dark olive back.

During the banding process the bander fans the bird’s wings to look for its wing molt stage, a method for aging the bird. Here’s a close look at a Tennessee warbler’s wing.

And finally, Tuesday was also a big day for Swainson’s thrushes (Catharus ustulatus). In the hand you can easily see the bird’s identifying feature, its buffy eye ring, but I was surprised by two things I’d never noticed before:

• Swainson’s thrushes have a two-tone beak. The lower mandible is not as dark at the face as it is at the tip.
• Swainson’s thrushes are small birds, though larger than warblers.

As I said before, if you’d like to see birds up close during fall migration, visit Nick Liadis’ Bird Lab website and scroll down to the list of three banding locations — Hays Woods, Upper St. Clair and Twin Stupas in Butler County — with instructions for contacting him to set up an appointment.

Learn more about Bird Lab on Wednesday 2 October when Nick Liadis presents Studying Migration Across a Landscape Gradient: Bird Banding in Urban, Suburban, and Rural Habitats at the Three Rivers Birding Club meeting at Beechwood Farms (and on Zoom).

Don’t forget to support Nick’s efforts with a donation at Bird Lab’s GoFundMe site.

26 September 2024

Two species of North America’s fall warblers are so easy to mistake for each other that the pair has gained a nickname. Meet the “baypoll.”

On Tuesday I visited Bird Lab’s Hays Woods banding station for an up-close look at fall migrants. That morning Nick Liadis and Shana banded magnolia warblers, Swainson’s thrushes, Tennessee warblers, ovenbirds and many other species. Best Birds were the two pictured above, found in the same net at the same time: a bay-breasted warbler and a blackpoll warbler. Were they traveling together? Maybe. See yesterday’s blog.

These two species look so much alike in autumn that birders joke that they’ve seen a baypoll when they aren’t sure which one it is. Baypoll = BAY-breasted / blackPOLL. eBird doesn’t accept that designation, of course, but it’s useful for describing our frustration.

How can you tell the two apart?

In non-breeding plumage the bay-breasted warbler (Setophaga castanea) has bold wingbars with a dark bar between them and often, but not always, a faint bay (chestnut) wash on its flanks. It also has dark feet and an unstreaked breast. Compared to other warblers the bay-breasted looks long and bulky, not petite.

Blackpoll warblers (Setophaga striata) are striped, striata, where the bay-breasted is not. Even when the stripes are faint you’ll see them at the sides of the breast. Wingbars on blackpolls are pronounced but not as emphatic as on the bay-breasted. Blackpolls have a more definite eyeline than bay-breasted, but the real clincher for a blackpoll is its yellow-orange feet! The bird may have dark legs but it always wears golden slippers. I have spent many frustrating minutes waiting for a blackpoll to show me its feet.

Notice the feet on both birds in the top photo, sticking out above the bander’s thumb.

So next time you see a baypoll, check out its feet.

If you’d like to see birds up close during fall migration, visit Nick Liadis’ Bird Lab website and scroll down to the list of three banding locations — Hays Woods, Upper St. Clair and Twin Stupas in Butler County — with instructions for contacting him to set up an appointment.

Support Nick’s efforts with a donation at Bird Lab’s GoFundMe site.

p.s. In breeding plumage you’ll never confuse a bay-breasted with a blackpoll.