Pin-headed, I Mean Brown-headed Cowbird

Day 209: It is uncharitable of me, I know, but I cannot look at cowbirds without remarking on how pin-headed they are compared to other birds. Contrasted with a parrot, for example, who is possessed of a brain able to manage tasks of higher learning (vocal, mechanical, etc.), a cowbird is easy to dismiss as a creature capable of survival skills and not much more. Yet the cowbirds' ability to mimic sounds is astonishing. I have personally heard them ringing telephones and honking horns, but one other vocal feat sticks the strongest in my mind. I was living in rural Thurston County at the time, surrounded by neighbours who had livestock of various sorts. I had gone out in the yard early one morning and was assailed by a whinny close by. My first assumption was that the cattle rancher whose pasture abutted ours had got himself a horse, but then I realized that the sound had come from above me, about sixty feet up one of the Doug-firs towering over our garage. It came again, that whinny, and again, somewhat higher pitched than a horse voice ("horse," not "hoarse"). After watching the tree for a while, I saw a Brown-headed Cowbird (Molothrus ater) fly out from among the branches. The whinnying stopped until the bird had returned to its nesting site, where it again took up the imitation. Over the years I lived there, there were many other occasions when I heard a horse up a tree. Apparently the sound was easy to reproduce, even for a pin-head.

Brown-Headed Cowbird Male

Day 209: Another of my "backyard birds," Brown-Headed Cowbirds exhibit sexual dimorphism, i.e., the males (shown above) are coloured differently than the females. The female is a nondescript brownish-grey, identifiable as a Cowbird most easily when she strikes the pose typical of the species: beak pointed at the sky, the spine in an almost perfectly straight line from the back of the head to the tail. For want of better terms, it makes them look pin-headed and silly, but Cowbirds are not as brainless as they may look. Cowbirds are brood-parasites, which is to say that they do not build their own nests but lay their eggs in the nests of other bird species. Because their eggs (sometimes as many as three dozen in a season!) develop more rapidly than those of their unwitting hosts, the young frequently outcompete the less-developed offspring of the nest-building species. The good news is that some hosts recognize Cowbird eggs when they see them, and may start a new nest on top of the Cowbird eggs, puncture them, or pitch them out of the nest altogether. So how do young Cowbirds know that in fact they are Cowbirds, and not, say, Warblers? Studies have suggested that they recognize both the call and the appearance of adult Cowbirds in just a few weeks from hatching, and may even examine themselves for comparison to adults, as was demonstrated when both young Cowbirds and adults were artifically marked. The young birds, seeing a distinctive marking on themselves, were drawn to similarly marked adults. That said, Brown-Headed Cowbirds are gifted vocal mimics as well. I spent some time trying to figure out how a whinnying horse had gotten fifty feet up an old Doug-fir at my previous home.

Brown-Headed Cowbird, Molothrus Ater

Day 201: The question was how a horse had gotten sixty feet up a Douglas-fir. I could hear it whinnying, over and over and over, clearly distressed by a lack of solid earth beneath its hooves. It was the first summer after my husband and I had taken over his grandparents' "ranch," a 10-acre spread with a pioneer-era house and no indoor plumbing. No one else in the family wanted it when the grandfolks offered it around. We jumped at the chance, moved out of a small Seattle rambler with all the modern conveniences and set up housekeeping with intent to improve the house or build a new one. It never happened, but that's not germane to the story. I was still trying to figure out how the horse got up the tree. Our neighbour ran cattle, but that soprano whinny wasn't coming from any cow. In any event, cows don't climb trees either, and the sound was coming from about halfway up the Doug fir behind the garage.

That was my first encounter with the amazing mimicry for which Brown-Headed Cowbirds are known. They can imitate a siren, a ringing telephone, cats, dogs, other birds and yes, horses, albeit rather high-pitched squeaky ones. There are no horses where I live now, but my Cowbirds mimic hawks and jays and, amusingly, jays imitating hawks, which Steller-fellers do quite well, thank you. By the time it reaches Cowbird pronunciation, a little has been lost in translation, but it's still recognizable and identifiable as a second-hand revision. The other distinctive trait of Brown-Headed Cowbirds is that between calls, they look up, as if searching the skies for flying saucers. "Hey, Joe? Do you know what them UFO things look like? I think I just saw one go over." Some people think they're pests, ranked right up there with Starlings, but I think they're funny. I mean, when I first met them, they were horsing around.

Hidden In Plain Sight

Day 310: You really don't want to go sticking your nose in the daisies around here. You never know who might be living there. Misumena vatia, the Crab Spider, is a master of camouflage, although its ability to change hue requires a protracted stay on the flower its coloration mimics. When it moves to a white or pale green blossom, it slowly excretes the yellow pigment normally found in the outer layer of cells. These spiders are very common in the Pacific Northwest, but are often overlooked because of their chameleonic talents.