Male Brown-headed Cowbirds have been engaging in courtship display in the backyard this week. Interestingly, they seem to display to each other in order to entice females closer. This is sort of like the multiple male displays one sees at a grouse or prairie chicken lek (see my earlier post on this), and serves a dual purpose of stimulating males to perform, while giving females a chance to compare their performances and choose the “best” male to fertilize her eggs.
The sequence of alternating displays begins with first one bird and then the other puffing up, spreading wing and tail feathers and bowing to the other bird while emitting a blackbird-ish, high-pitched call note.
The short video clip below by Bradley Yee illustrates the sequence of displaying male Brown-headed Cowbirds very well.