A few weeks ago, my wife Emily and I packed up the toddler and the dog and headed to what has become a special place for us, Mt. Desert Island in Downeast Maine.
It’s one of those places where every view could be on a postcard – it looks and smells like they distilled pure, concentrated Maine-ness in an Erlenmeyer flask and poured it onto this island. I highly recommend a visit. But what does any of this have to do with Cape Cod birds? Well, it turns out that these mossy spruce-fir forests hold some clues about what birds we may, or may not, be seeing around here this winter.
Every year, a biologist named Ron Pittaway prognosticates about what we should expect to see among of a suite of birds called “winter finches”, birds who move south erratically each winter in response to food crops of various trees in the boreal forest. This type of migration is known as “irruption”, with an “i”, and stands in contrast with the regular, predictable southward and northward movements of most migrant birds.
The vast, boggy boreal forest, dominated by spruce, fir, tamarack, aspen, and birch, stretches from northern New England to Alaska, and all across higher latitudes of Asia, where it’s known as the “taiga”. While some tough-as-nails birds like chickadees and Golden-crowned Kinglets can find insects year-round in these frequently frigid forests, most species depend on seeds and fruits of certain trees to survive the winter there.
So Ron takes reports on these seed and fruit crops from sources across Canada, then makes predictions about whether us relative southerners will see species like Red and White-winged Crossbills, Common Redpolls, Purple Finches, and Pine Siskins, as well as unrelated but also irruptive species like Bohemian Waxwing and Red-breasted Nuthatch.
Some of these, like the crossbills, depend on conifer seeds. Common Redpolls favor birch and alder seeds, while Bohemian Waxwings and Pine Grosbeaks love the brilliant red-orange fruits of Mountain Ash trees. Even Blue Jays, who we expect to see year round, have big movements in response to regional production of acorns, and beech and hazel nuts.
Last winter we were lucky to have at least small incursions of species like Red Crossbill and Evening Grosbeak. So what can we expect this year? According to Ron, not much, as the northern forests are replete with cones, seeds, and fruit, which means the birds will stay put up there. My own observations in Maine confirm this – the spruces were dripping with cones everywhere we went, and beeches and Northern Red Oaks were laden with acorns and nuts. I enjoyed a small flight of Red Crossbills at our cabin on our last morning, perhaps the only ones I’ll see this year.
It’s ok – the boreal forest can keep their birds this year. After all, it’s their scarcity and unpredictability that makes these species irresistible - whether in dating or birding, playing hard to get works. Besides, they need them more than we do – I had a mere 37 species of birds during my five days on Mt. Desert Island. Here on Cape Cod, with the right scouting and intel it’s possible to see over 100 species in a single day, even in January. But if you really want your winter finch fix and don’t feel like driving to Algonquin Provincial Park in northern Ontario, check out Cornell’s feeder cams, which typically have a finch-rich offering from Canada. Just don’t forget to look out your own window – I’m sure you’d hate to miss that Bald Eagle perched on your deck because you were watching someone else’s feeders on TV.