Earlier this month we spent a weekend at Kidney Pond, as I had mentioned in a previous column. What’s great about this location is the variety of habitat immediately surrounding the campground: spruce/fir and mixed deciduous forests march down to the pond’s marshy edge near its outlet, where emergent vegetation creates another world for water birds and those that nest near its margins. Although the breeding season has long since passed, birds still used this location – albeit in fewer numbers.

One morning I got up early and followed a little trail called “Moose Look,” down to this location. It was a beautiful morning; the pond’s surface was smooth as glass, and the rising sun bathed the mountains in a beautiful glow. I stood quietly at the water’s edge and soon heard the unmistakable notes of blackbirds – but not our familiar red-winged blackbirds. What approached me from the other side of the pond was a small flock of rusty blackbirds, lesser-known denizens of the boreal forest.

The flock alighted in a tall white pine just within the edge of the woods. Their calls had the familiar liquid tones associated with red-winged blackbirds, but were a little less strident, with more of a squeaky, rusty-hinge quality to them. This isn’t what gives them their name, however; the moniker refers to their plumage. During the fall and winter, the edges of their black feathers turn a light brown, making them appear “rusty.”

There are no less than five species of blackbirds that breed in North America. Here in the Northeast, the two most likely to be seen are the red-winged and the rusty. The rusty blackbird, however, breeds much farther north than does the red-winged – to the tree line across Canada and the northeastern United States, and far into Alaska, in fact. It also prefers different habitat: whereas the red-winged frequents fields and breeds in open marshes among cattails, the rusty is more of an arboreal bird. Its nests, which are reported to be exceptionally large and sturdy, are constructed in trees and shrubs near or over water.

Here in Maine, the rusty blackbird’s breeding range occupies the northern half of the state, while the red-winged breeds throughout. The rusty blackbird winters entirely in the southeastern and midwestern United States.

In appearance, the rusty obviously lacks the red “epaulets” of the red-winged, and seems to be daintier. Its beak is thinner with a slight downward curve. Its tail is longer, and it has a pale eye (the red-winged has a dark eye).

The flock of rusty blackbirds called to each other as they perched atop the trees. Their dark plumage contrasted with the greens of the pines and the vibrant yellows of the turning birches; they would soon be leaving.

NEWS bird columnist Chris Corio can be reached at bdnsports@bangordailynews.net