Rusty blackbirds seem to be regulars
Ten rusty blackbirds dropped into our backyard last week. This was not a surprise, exactly, but it wasn't anticipated. Seeing a rusty blackbird can never be anticipated.
This is a species on the brink. The number of rusty blackbirds has diminished dramatically in the last several decades, accelerating a decline that may have begun as much as a century ago. No one knows why exactly this should be so. The circumstances do sweeten each rusty blackbird sighting.
Rusty blackbirds seem to be regular migrants in the Red River Valley. Checking my file of this column, I find that I've reported rusty blackbirds about this time in each of the last three years. I also found several references to rusty blackbirds in winter.
The preponderance of sightings in fall and winter fits what is known of the rusty blackbird's life cycle. They nest across Canada, reaching U.S. territory only in Alaska, extreme northeastern Minnesota and northern New England. The nests closest to Grand Forks are likely around Lake Winnipeg, about 150 miles north of here. These black birds spend winters in the southeastern United States, from Iowa and Illinois to the Gulf of Mexico.
The passage from nesting ground to winter range brings the rusty blackbirds to the Red River Valley. The opposite may well be true, but rusty blackbirds are seldom seen here in spring. Two reasons account for this. One is that spring migration is rapid as the birds press northward toward the critical business of their lives. The southward migration in fall is more leisurely, sometimes occupying a month or more. Some blackbirds linger into the winter long enough to be counted on Christmas bird counts. They've occurred on 15 such counts in Grand Forks, and they've been spotted on counts in Crookston and Icelandic State Park near Cavalier, N.D.
The bird's appearance also may account for the relative lack of spring sightings. In spring, the rusty blackbird is a black bird easily confused with its relatives, especially the Brewer's blackbird. Both are glossy black with some iridescence and both with striking yellow eyes.
In fall plumage, the rusty blackbird is easier to identify. Then, it is a mottled patchwork of rusty brown and dull black tending to gray. The facial pattern is distinct, showing a fairly prominent whitish patch behind the eye and a black mask-like blotch below it. Don't expect uniformity in appearance, though. Rusty blackbird plumage is highly variable. The constant is the presence of the rusty color, and that's what gives the species its common name. Unlike most species, the rusty blackbird is not named for its breeding plumage but for its off-season attire. Perhaps that's because the bird is more obvious and easier to identify then; perhaps it is because the rusty blackbird is a winter bird in the United States.
Rusty blackbirds sometimes occur with other blackbirds, but all of the birds that dropped in at our place west of Gilby, N.D., were rusty. To my eye, they literally dropped in. I saw them descend from an evergreen tree onto the ground where I'd grown tomatoes during the summer. Perhaps it was the garden detritus that attracted the blackbirds. Or they might have been foraging for insects and grubs that might have been hidden in the litter.
Rusty blackbirds are opportunists when it comes to food, taking both plant and animal material. They kill other birds, at least occasionally. I found one vivid account in "The Birds of Manitoba," in which a rusty blackbird decapitated a white-throated sparrow. Other references suggest rusty blackbirds kill other birds and feast on their brains.
This sounds like grackle behavior, and I briefly considered that the birds in my tomato patch were grackles. Not so, however. These were smaller birds, showing more variation in plumage than grackles would. What's more, they were silent, while the grackle is a noisy bird.