Spring for Red-winged Blackbirds

Tue, 03/13/2018 - 5:45pm

As we struggle to believe that spring is indeed on the way despite an onslaught of winter storms, we find hope in the arrival of the earliest spring migrant birds. We wrote about one of those last week, the red-shouldered hawk. But relatively few people get to regularly see red-shouldered hawks here in Maine and if they do, they’re not sure what they’re seeing. Many birders are now reporting hearing the buzzy “peent” sounds of the first arriving American woodcock, another very cool bird but one that is more often heard than seen.

Perhaps the earliest spring arrival that is most universally seen and recognized is the red-winged blackbird. Like the red-shouldered hawk, the red-winged blackbird winters regularly just to our south, in southern New England (a few sometimes hang on into December at a few feeders even here in Maine). That means they don’t have so far to travel to get here early. A few red-winged blackbird arrivals are always noted in the southern tip of Maine sometime in February, followed by a flood of them showing up across at least the southern half of the state by March.

It is always the males, with their shiny, all-black plumage accenting the brilliant red shoulder epaulets bordered by a vivid yellow. For us, it is their song that really makes it feel like spring. The male red-winged blackbird opens its bill wide and belts out a rousing “onk-er-leeee,” often singing from the top of a tree in or near a marshy wetland. A few weeks ago we were treated to a small group of red-wings each competing for the loudest “onk-er-leeee” as they sang from some trees above a small frozen wetland. These were our first red-winged blackbirds of the year and were a very heartening sight and sound signaling that spring is on the way.

After their arrival, red-winged blackbirds sometimes are rather forgotten by us bird lovers as the flood of sparrows, warblers, orioles, grosbeaks, and other birds begin arriving. So some may be surprised to learn that the red-winged blackbird has some fascinating and surprising breeding behaviors.

Those early arriving male red-wings have good reason for trying to be the first back to their wetland breeding site of choice. When males get to their breeding site, they find the part of the marsh that they surmise will have the most food and provide the best nest sites, and they defend it from all other males. When the females arrive some weeks later, they choose the male and the territory that looks the best to them. That’s pretty common among bird species, but what is interesting about red-wings, though, is that each male’s territory will have many females nesting within it. In more scientific terms, they have a polygynous mating system. In one case, 15 females were within the territory of one male. The average, however, is much less—each male will have five or so females in his territory.

Before the advent of genetic testing, ornithologists assumed that all the young in each male’s territory were sired by that male. In recent years, that assumption has been turned on its head. While the majority of the young within a given male’s territory are indeed his offspring, a surprising number are often from the females mating with males from nearby territories, or even from so-called “floater” males with no territory that sneak around within the system.

In the coming weeks you may want to find a marsh near you and spend some time quietly watching to see if you can get a peek into the secret lives of your local red-winged blackbirds.

Jeffrey V. Wells, Ph.D., is a Fellow of the Cornell Lab of Ornithology. Dr. Wells is one of the nation's leading bird experts and conservation biologists and author of the “Birder’s Conservation Handbook.” His grandfather, the late John Chase, was a columnist for the Boothbay Register for many years. Allison Childs Wells, formerly of the Cornell Lab of Ornithology, is a senior director at the Natural Resources Council of Maine, a nonprofit membership organization working statewide to protect the nature of Maine. Both are widely published natural history writers and are the authors of the popular book, “Maine’s Favorite Birds” (Tilbury House) and the just-released “Birds of Aruba, Bonaire, and Curaçao” from Cornell University Press.