This morning on my route to check for casualties at the NRC, I found a tuft of mostly contour feathers that had been cleanly sheared from their owner: At some point in the past day or two (I didn’t check yesterday), a bird hit a window and was scavenged before I could claim it. Not far away (same side of the building, ~ 20m away), I found a primary feather from a different bird that had also been scavenged! So we had two birds hit, and both were scavenged, in the past couple of days.
I am quite confident that the tuft of contour feathers came from a PAINTED BUNTING. The edges of the feathers are green, not olive like we might see in any number of species, but clearly green. Other than parrots (of which we have no naturalized species in our area), it’s really just Painted Bunting that could have left feathers like these.
The primary feather has a warm, brown edge to it – almost rusty. Given its size and color, likely candidates include Great Crested Flycatcher or one of the Catharus thrushes, of which Swainson’s is moving through in numbers these days.
I had pretty well convinced myself that the primary feather came from a Swainson’s Thrush, when on 12 May I discovered a window-killed Swainson’s Thrush at another building on campus, the Kerr Residence Hall. Looks like the right size, shape, and color to me:
I found a third Swainson’s Thrush window kill at Ag Hall on Friday, 14 May. So that’s THREE Swainson’s Thrush casualties on the OSU campus in four days, all found in one rather small corner of campus.
Now there are a lot of Swainson’s Thrushes in the world, and they’ve got a broad breeding distribution across the great boreal forest of the Nearctic. But this is what I’m talking about when I say that long distance migrants face greater risk from window collision mortality that short-distance migrants and residents. In less than a week, one guy found three window-killed Swainson’s Thrushes in an area of about 6 ha in one unremarkable little corner of Oklahoma. How many were possibly killed overall this week? Considering the broad front of migration this species is using this week, is the number dozens, hundreds, thousands?