What’s blue and orange and generates a lot of questions from listeners? The answer is the Eastern Bluebird, everyone’s favorite neighborhood songbird. Especially your grandmother. While it may not seem like the right time of year to talk bluebirds, they can be fairly common in winter, and some lucky folks even get them in their yards.
If you have the right kinds of fruiting trees and shrubs, some water, and maybe suet, you have at least a fighting chance of a visit from your local bluebirds all winter long.
Eastern Bluebirds breed across the eastern two thirds of the United States and southern Canada, and winter widely within the same range. They are even year round residents in the piney mountains of Mexico and Central America. They eat mainly insects during the breeding season, but can subsist on fruit during the winter, which helps them stay as far north as southern Canada year round. Because their wintering and breeding ranges overlap so much, it’s tough to tell migrants from local residents, and their migrations are still poorly understood.
Beyond that gorgeous electric blue plumage, another reason people love bluebirds so much now is that they didn’t used to be so common. Conversion of farmland to forest, competition with House Sparrows for nesting cavities, pesticides, and the absence of beavers led to a 90% population decline in the northeast by the 1970s. If you were listening, you might be saying “wait, what do beavers have to do with bluebirds?”
Beaver dams flood forests and kill trees. When the beavers eventually move on, the dam fails and the pond drains to become a lush, insect-rich meadow peppered with dead trees perfect for cavity nesting birds like bluebirds. The return of beavers to the Massachusetts landscape was a boon for bluebirds, Great Blue Herons, Hooded Mergansers, woodpeckers, and other birds that need swamps and dead trees for nesting. We don’t have beavers here on the Cape, so the main reason for their comeback in these parts is people. An army of doting volunteers has built and maintained a landscape full of nesting boxes and helped keep the House Sparrows and starlings at bay.
The Cape Cod Bird Club maintains nesting boxes at Crowe’s Pasture in Dennis and at three conservation areas in Harwich in cooperation with the Harwich Conservation Trust. I also have volunteers monitoring a ton of boxes at Wellfleet Bay sanctuary, plus some other spots in Eastham and Wellfleet. All of this data goes to Cornell’s NestWatch program, and if you monitor nesting birds in your yard, please check out the NestWatch website and contribute your data to this valuable citizen science project.
If you want to attract nesting bluebirds to your yard, you’ll have the best chance if you have a lot of open grassy land. Having adjacent open space like powerlines, cranberry bogs, golf courses, and even capped landfills can help. In winter they can be almost anywhere, but deep cold and snow often drives them to backyards with open birdbaths and suet feeders. They also like live mealworms, so if you’re into having a bucket full of wriggling worms in the basement, you’ll have a leg up on the competition.
Just now as I was finishing this report I heard a bluebird calling outside, and found a flock of 8 in my neighborhood – the first ones I’ve seen all winter. As is often the case, they were part of a roving super flock that included dozens of goldfinches, House Finches, juncos, and a ton of robins. I grabbed my camera and headed out, but soon a Sharp-shinned Hawk that had been tailing the flock busted in and broke up the party, ruining my chances at a photo. Sometimes the birds are so uncooperative, I wonder if they even know that I‘m the bird guy?
This piece first aired in January, 2017.