Always in season: Rose-breasted grosbeaks are doubly well named
Ahem, dear reader: The subject this week is bird breasts.
To be sure, the breast is not the first part to examine when trying to identify a bird. The general impression of the bird is the first thing to notice: its size, shape, length, the size of its bill, the length of its tail, its way of sitting, its pattern of flight.
Then check the details. To be sure, the breast may be one of these.
This is the case with the rose-breasted grosbeak, as is demonstrated in its name. The brilliant color of the male grosbeak's breast will clinch its identification against any other species. It's a definitive field mark, in other words.
But it's not really necessary to see the breast to know the rose-breasted grosbeak. The species is identifiable in other ways, and at first sight.
The grosbeak is a heavy set bird, and it appears two-toned in color, black and white. The wings show large white patches. The tail is neither long, nor stubby, nor tapered. Its contribution is to the impression of a solid, well-proportioned bird.
The beak, on the other hand, is outsized, another aspect of the bird that's noted in its name. Bird beaks are often important clues not just to the identity of bird species but to their lifestyles. The grosbeak is a seed eater. Its bill is adapted to crushing, the better to get to the tasty and nutritious hearts of such foods as sunflower seed.
This brings rose-breasted grosbeaks into our backyards. They are frequent visitors at feeders, and they can be quite conspicuous at this time of year.
Of course, we are discussing male grosbeaks here. Females are much plainer, being streaked with brown and white the better to wait unnoticed on the nest. Females are identifiable, though, because they share the general impression of the grosbeak: a solid, well-proportioned bird with a big bill.
There are five species of grosbeaks all built this way. The rose-breasted is immediately separable among these because of its breast. Two other species occur here, but only in winter. Pine grosbeaks, delicately colored, pinkish birds, are fairly common in winter; evening grosbeaks less so, and apparently diminishing in occurrence here.
The remaining grosbeak species do occur here. These are the blue grosbeak, historically a southern bird that has been expanding northward, and the black-headed grosbeak, a bird of the west.
North Dakota is at the middle of the continent, and both blue grosbeaks and black-headed grosbeaks occur here. The first is unusual; the second is frequent in the western part of the state.
Black and rose-breasted grosbeaks are closely related and occupy the same type of habitat. Where their ranges overlap, they do interbreed, and there are discussions of hybrids from North Dakota in ornithological literature.
Despite their closeness, the birds are only superficially similar. That is, both would be recognized as grosbeaks, solidly built birds with big bills. The black-headed grosbeak is also a two-toned bird with big patches of white in the wings. The two dominant colors are black, as the name suggests, and orange, which occurs on the belly, breast, and lower back, across the nape of the neck and behind the eyes.
The grosbeaks are birds of open woods and shelterbelts. Tree planting across the Great Plains has helped the grosbeaks expand, bringing black-headed and rose-breasted grosbeaks together. Rose-breasted grosbeaks are far more likely in the Red River Valley, though I have seen black-headed at our place west of Gilby, N.D.
Grosbeaks are finches, like the sparrows, and one species of sparrow might cause momentary confusion. This is Harris' sparrow, among the largest of the sparrow species, though still smaller than the grosbeak. The confusion arises from the bill, not especially large in the sparrow, but especially prominent, because it stands out against the black front of the bird. This extends onto the breast, giving the Harris' sparrow the impression it is wearing a monk's cowl, as the older bird books like to say.
In backyards, the grosbeak might be mistaken for a robin, but a second glance will tell the difference. The robin has a relatively delicate beak, and its belly as well as its breast is brick read, rather than rosy.
The sparrow and the robin are ground-loving birds; the grosbeaks come to ground, but they much prefer to feed at some height, often choosing tray feeders. In breeding season, they are difficult to see, because they spend much of their time in the tree tops.
Harris sparrows are strictly migrants here, and the bulk of them have passed through the area by now.