Rusty blackbird, declining and rare

The common black birds of North America, the crow, the grackle which is also called the crow blackbird, the red-winged blackbird, cowbird, buzzard or vulture are recognized by everybody who recognizes a robin. Here’s another black bird of North America, the rusty blackbird. This is a bird that is described in most of the bird books I have as common. It may have been common but not any more. Now it’s rare.

The rusty blackbird is cowbird size. A male in breeding plumage is black with a faint greenish iridescence on its back, an iridescence which is visible only in bright sunlight. A female is dark gray on the head, back, wings and tail, lighter gray on the throat, breast and belly.

A male rusty blackbird in non-breeding plumage has brownish spots on its back, wings and tail and is brown on the throat and upper breast. A female in non-breeding plumage is brown on its head, back, wings and tail with a lighter brown stripe from the base of the bill up over the eye and is light brown on the throat, breast, belly and under tail coverts. Both male and female have bright yellow eyes in breeding and non-breeding plumage.

Rusty blackbirds are birds of the north, the far north, like juncos and tree sparrows. Their summer range is Canada, from the Atlantic Coast to the Pacific, and Alaska. There they nest in wet woodlands, bogs and swamps. In winter they fly south, also like juncos and tree sparrows. Their winter range is Minnesota, Michigan and New Jersey south to the Gulf of Mexico and all but the southern tip of Florida and from the Rocky Mountains to the East Coast.

I haven’t seen a rusty blackbird in several years. Or maybe I have but didn’t recognize them. They are inconspicuous, just little black and gray and brown birds.

The rusty blackbird is named for its color, obviously, Like goldfinch, scarlet tanager, indigo bunting, blue grosbeak and red crossbill, to name a few. But those birds are named for their color when in breeding and nesting plumage. The rusty blackbird is named for its color in non-breeding plumage, its eclipse plumage, fall and winter. Those brown spots it has then look like spots of rust.

Perhaps when my bird books were published the rusty blackbird was fairly common though I don’t remember seeing them often. Now, however, the rusty blackbird is certainly not common. In a recent report by the Cornell Laboratory of Ornithology I read that rusty blackbirds have decreased by more than 90 percent.

Many small birds have decreased in number in recent years. Numbers from Christmas bird counts, spring birding big days, breeding bird surveys and bird banding all indicate a decline in small birds. One report I read stated that many species have declined by as much as 40 percent.

Some small birds have increased, red-winged blackbirds for example. A hundred years ago Dr. Arthur A. Allen of Cornell University wrote that red-winged blackbirds were common in cattail marshes during their nesting season but never seen far from cattails. Redwings have adapted and now more numerous than they were when Dr. Allen wrote of them. They still nest in cattail marshes but they also nest in hay fields and along grassy roadways. There are five male redwings on the bird feeder outside my study window now.

Cardinals and tufted titmice have also increased and they’ve expanded their range. These were birds of the south when I was young. Southern Indiana was the northern limit of their range. Now both nest commonly around my home in northern Indiana and north into southern Canada.

But back to the rusty blackbird. Why has it declined by so much more than other small birds, more than twice as much as other small birds?

Neil Case may be reached at neilcase1931@gmail.com.

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