Thanks to Corey Riding & Co. for checking the Noble Research Center while I was away on 6/9 and 6/10.
The cuckoo and House Finch carcasses remain.
I learned on 6/15 that Chrissy Barton from Corey Riding’s team actually did find a window-killed Black-and-White Warbler on the evening of 6/11. The bird is a SY female, and I think I see a gap in the breast feathers that would point to a brood patch . . .
Our first migrant of 2014 was this unfortunate Black-and-white Warbler. She’s female and I aged her as a second-year bird (molt limit was more obvious in direct light) with fat = 1. She was on the north side of the building though our winds were strong from the south yesterday and today.
There was a pretty good flight of migrants overnight behind storms that flared up in Kansas. Check out the stream of migrants in south Texas. Those will be coming through tonight, and might drop out as we’re expecting a powerful cold front to move through here.
The official start to fall migration began this morning with a beautiful ASY male Black-and-White Warbler. He had no visible fat and I found him on a south face to the building but approaching mid-August it’s difficult to imagine him as a local disperser rather than a fall migrant. Here’s the odd place he showed up:
I noticed him from some distance away. I was thinking this morning how even an errant leaf catches my eye. My detection rate is lower than 100%, but not by much.
Birders not used to seeing Black-and-Whites in the fall can be distracted by the white throats of adult males and misidentify a bird like this as female. The one character that only the adult males possess in all plumages is, however, evident on this guy: black auriculars (“cheek patch”).
I found an apparent SY female Black-and-White Warbler at the northwest corner of the NRC this morning. The bird had the stunned look of one who’d knocked into a window, but it wasn’t really trapped the way other birds I’ve found have been. After a few minutes and as I began to approach, it flew strongly to a nearby tree.
The north entrance and northwest alcoves were deadly again last night. This time the victims were an ASY female Black-and-white Warbler and an AHY Clay-colored Sparrow. The Dickcissel and Lincoln’s Sparrow carcasses have been removed.
Clay-colored Sparrow at the northwest alcove
Female Black-and-white Warbler at the north entrance.
Casualties piling up at the Noble Research Center
It’d been a few days since I had checked the Noble Research Center, and we’d had a few storms during that time. June 1st was actually just a plain, old rainy day – very unusual. Given the unusual weather, I figured there might be something waiting limply at the base of a window. I did not, however, anticipate that it would be a resident bird: an adult Mourning Dove:
Given the state of decomposition on this bird, I will assume that it died at least one day ago. It might have been longer, but I will consider for my analysis that it died on June 2nd.
Next, I was surprised by a window-killed Black-and-white Warbler. This was a bedraggled and somewhat decomposed 2nd year female, and for my records I will also consider June 2nd as the date of death. This is at least the second time that I’ve found a Black-and-white Warbler in June. What to make of these birds? It’s well past the normal spring migration for this species (March and April here in Oklahoma), and late enough that this movement could be post-breeding dispersal.
Here is a range map for Black-and-white Warbler:
While they breed far to the north in Canada, they don’t even range into Alaska. I wouldn’t be too surprised to find something that breeds way north like a Wilson’s Warbler at this time of year, given that some of its breeding range might just now be productive for breeding. So it doesn’t make sense – at least to me – that there should be migrants streaming north this late in the season.
Check this out though – frequency of Black-and-whites in eBird checklists:
Well there it is. You see two distinct peaks of the species appearing on checklists that obviously indicate spring and fall migration, respectively. But where we might expect a steep drop in reports at the end of May, there’s actually a little bit of a bump in early June. Now that could just be people finding them on territory where they breed, but it could also reflect movements of Black-and-whites that cause them to be detected in other places as well. Given that we have found fully fledged Black-and-whites as early as 28 April, I’m suspicious that there is a bit of post-breeding dispersal that I might be experiencing with these window-killed birds in June. Anyway, here’s the bird: