I’d truly hate having to name a favorite bird: there are roughly 10,000 species in the world, and I think they’re all unspeakably cool. But of the species likely to be found in March on Martha’s Vineyard, I can easily answer the question of which bird makes me happiest to see. It’s the eastern bluebird, beyond question.
Partly, the pleasure I take in encountering this bird derives from its history over the past half century or so — that is, during the period of my life to date. As a child growing up outside of Boston, I knew of bluebirds from the field guides my family always kept handy, and I yearned to see a bird that was so — well, so blue. But bluebirds are highly insectivorous, and the 1960s were back in the days of widespread use of DDT. Other factors, such as competition for nest sites and a dearth of suitable habitat in the largely suburbanized landscape I lived in, no doubt contributed to the bluebird’s scarcity. But mainly, this elegant bird was collateral damage in our war against the mosquito.
It wasn’t until my teenage years that I finally found this bird, as the use of the worst pesticides tapered off prior their eventual ban in 1972. I still remember my first bluebird plainly, a brilliant male seen as I bicycled through Lincoln in the summer of that year. Since then, bluebirds have grown steadily more common in southern New England, and every one I see reminds me that nature is resilient and some ecological catastrophes are reversible.
But the bluebird would be a favorite even it hadn’t dodged distinction. A relative of the thrushes, robins, kinglets, and wrens, the bluebird, especially adult males, is a stunningly beautiful species. The blue of the bird’s back and wings is simply the prettiest color in nature. Moreover, these birds are gregarious, active, and flexible in their behavior — all in all, great fun to watch.
This past winter, I have received many reports from observers who were surprised to have encountered bluebirds during this season. But like the American robin, the eastern bluebird entirely vacates the Vineyard only during protracted runs of extreme cold or deep snow cover. In a typical winter, the species is not hard to find, and the fact that most Islanders don’t see bluebirds in winter tells us more about human inactivity than about the status of the bird. Like most other members of its family, a bluebird may prefer insects as food, but will happily switch to fruit when insects are unavailable. This versatility helps bluebirds survive cold weather. Once, in extreme cold, I found a communal roost of bluebirds, more than a dozen huddled together in the crotch of a tree for warmth.
Indeed, though it is not the same individual birds that are here, the eastern bluebird is a year-rounder on the Vineyard as species. Numbers are undoubtedly highest during fall migration, when an astute observer can often find dozens in a day. Many of these will be high overhead, just passing through and best detected by their flight note, a musical “toodle-loo.” During the nesting season, bluebirds are fairly common in agricultural areas and along woodland edges. Their song, a soft, musical warble, is unobtrusive, and the birds themselves, while not exactly shy, are not conspicuous. So most Islanders are probably unaware of how many bluebirds nest here.
In March, the bluebird population begins to shift northward to breed (the species nests north through New England and into the Maritime Provinces), producing a spike in numbers on the Vineyard. Males also begin singing, making them somewhat easier to detect (and, if the male is lucky, attracting a less colorful female to mate with). Birds that will remain to nest here begin investigating cavities as possible nest sites – bird boxes, of course, but also holes in stumps and tree trunks. And as the weather warms and insects once again become active, this elegant bird reverts to its favorite foraging method: perched on a fence or post, a bluebird will scan for motion on the ground beneath and then drop onto its prey like a tiny hawk.
In rural areas, setting up nest boxes for bluebirds is a popular activity, and one that undoubtedly benefits this species. As with any kind of nest boxes, bluebird boxes need a measure of maintenance and care to work well. In particular, bluebirds are often displaced from nest sites by house sparrows, an aggressive, non-native finch often found near barns and livestock, and would-be bluebird hosts should be prepared to play rough with house sparrows if they are serious about their nest boxes. (A great resource for learning how to encourage bluebirds and other cavity-nesters is the website www.sialis.org.) But it’s worth the effort to encourage this elegant bird, for its song, its role in controlling insect numbers, and above all because of that blue.