The next morning from the window I see a bird perching on a crooked TV antenna across the street. It's the Bronzed Cowbird.
Bronzed Cowbirds are black, thick-billed birds with red eyes. Though females are dull, the males' blackness shines with iridescent greenish and bronze shades on the body, and blue and purple on the wings, tail, and rump. This morning the male I see must have a female in sight, for he is puffing out his neck feathers, his "ruff," so magnificently that he looks as if he has two golf balls, side by side, lodged in his throat.
This is only one attention-getting feature of the Bronzed Cowbird's courtship behavior. Male Bronzed Cowbirds are famous for their bizarre strutting and hovering "helicopter" flights. I wonder why, here in early November with mating season presumably so far away, this male is puffing out his ruff?
Like the similar Brown-headed Cowbirds so abundant throughout most of North America, Bronzed Cowbirds neither raise their own families, nor do individual males and females pair off during the mating season. Bronzed Cowbirds, like their North American cousins, are "brood parasites."
In other words, two Bronzed Cowbirds casually mate after a great deal of male exhibitionism, the female becomes pregnant, and when her time comes to lay an egg she slips off, finds a nest of another bird species, typically a passerine (songbird, not a hawk, duck or the like), and when the other bird flies off her nest for one reason or another, the cowbird sneaks into the nest and deposits her egg. Sometimes the returning nest-owner recognizes that an alien egg has been deposited and that egg is destroyed or removed. American Robins and Northern Catbirds often do this. Sometimes vireos and certain warbler species cover all the eggs with a new nest floor and start egg-laying all over again.
But very often the subterfuge succeeds and the foster parents take care of the cowbird along with their legitimate offspring. Cowbird nestlings beg for food so aggressively that their nestmates may go hungry. When the young cowbird is fledged it joins others of its kind and the parasitic cycle continues.