Vol. 43, No. 2
This issue’s mystery species features a study (mostly) in black. In fact, the birds in the photograph are blackbirds (family Icteridae), which would seem to make their identification straightforward. As is often the case with "At a Glance" photos, however, there are features of the birds that seem distinctive and, at the same time, ambiguous. This uncertainty is partly due to the fact that more than one species is represented in the photo.
First, look at the appearance of the bill on the right-hand bird in the foreground. It is stout and distinctively shaped, which is somewhat atypical for a blackbird. Most icterids—Baltimore Oriole, for example—possess relatively long and sharp-pointed beaks, although others, such as the Common Grackle, have relatively stout and gently curved beaks. The blackbird in the foreground, however, has a thick, conical beak reminiscent of a sparrow or certain other seed-eating species. This distinctive bill shape, coupled with the uniformly glossy black appearance of the bird’s wings and body, identify it as a male Brown-headed Cowbird (Molothrus ater). Furthermore, at least two other blackbirds in the photo have prominently cocked tails suggesting that these birds are also cowbirds. The cocked tail of feeding cowbirds is often an easy way to pick them out of a mixed flock of ground-feeding blackbirds.