Not long after returning with some negative data for the Noble Research Center today, I received a call that there were two dead “gray and yellow” birds at the OSU Multi-Modal Transportation Facility. This is about a par-4 drive from the NRC, just to the north across Hall of Fame Avenue. It’s a building with a good bit of glass, but it also presents a hazard away from the building itself: glass bus stops. Here was the offending one today.
And here, its victims: two Western Kingbirds. They might have been carried away in springtime romance when they collided, maybe they just met. More likely they have a nest underway in the vicinity, as most other kingbirds on campus seem to be on eggs but haven’t started incubation.
The birds gave me a chance to study Western Kingbird a bit more closely. Check out the male’s flaming crown patch (the female had one that was smaller and more of a dull orange).
Ageing and sexing kingbirds was, I learned, a fascinating prospect. I used (in part) these criteria from Pyle:
Tyrannind flycatchers are “primitive” members of the Passeriformes, meaning that they retain ancestral characters. One of those is that, unlike most songbirds you know that have 9 primaries, Tyrannids have 10. In the case of Western Kingbirds, the shape of the tip of that 10th primary is useful for determining age and sex. It’s long, emarginated, and exceedingly narrow in adult males and correspondingly shorter and more broad in adult females and younger males. The same goes for the shape of primary #6. Here are photos of p10 and p6 for the male:
Here are those same feathers on the female:
I aged the male as ASY. He weighed 42g but had no fat laid down. His CP = 1, his wing was 126mm and his tail was 87mm. The female (also fat = 0) was an SY weighing 38g. Her BP = 1, and her wing and tail measurements were 119 and 82mm, respectively. As further evidence that the female was SY, check out the contrast between her molted and replaced central rects (the black ones with the white shaft) and those poor, dusky brown and worn other tail feathers that she grew in the nest somewhere last summer: