Sept. 30, 2005
My friend Will had predicted that today would be a major hawk migration day. Of course, he meant down on the coast at his favorite hawk-watching spot not 30 miles inland here along the Kennebec River in Maine. But just last week I had stumbled into a push of Broad-winged Hawks (and nine other species) right here. I had ended up counting over 400 hawks, mostly Broad-wings, that came over the river and ascended the elevators of rising air right over the little bustling town of Hallowell.
Sure, I knew that it was probably just a lucky break. But I couldnï¿½t take the time to drive down to the coast today so I figured I could at least try for a few hawks from the office porch over lunch.
I was ready for hawks but what I saw instead startled me. As I scanned the horizon, small birds in flocks of five or ten kept appearing. Flying low, just over the tree tops, and occasionally dropping out of sight behind trees, they came closer. Finally, seemingly reluctantly (a few even turned back) they came over the river and dropped quickly into the trees and shrubs on the bankï¿½chickadees! Black-capped Chickadees!
This may not seem like something that an ornithologist would find surprising. Chickadees are certainly a common bird familiar to all birders and people who feed birds. But we tend to think of them as sedentary, non-migratory creatures. It is known that some portion of the Black-capped Chickadee population migrates every year. In some years the numbers moving south are so large that it is labeled as an irruption.
The Black-capped Chickadees I saw were clearly migrating. Unlike most songbirds, chickadees do not migrate at night (or at least we have no evidence that they do). They move low, from tree to tree, avoiding large areas of open space. This way they hope to elude the Sharp-shinned Hawks and Merlins watching for an easy snatch to provide a quick lunch.
I had actually noticed several flocks of Black-capped Chickadees moving rapidly through the trees and over rooftops earlier in the morning when I dropped my wife off at her office. At the time I had wondered if they were migrants or just a very large and extended flock of resident birds (as unlikely as it seemed). Now, I was certain that I was seeing what might be the beginning of a large Black-capped Chickadee irruption.
As common and widespread as Black-caps are in North America, an amazing 26% of their global population is estimated to breed in the Boreal! My guess is that most of the irruptions of Black-capped Chickadees into eastern North America are probably made up of birds that originate in the Boreal.
Will others start reporting large numbers of migrating Black-capped Chickadees as the season progresses? Is this just a local phenomenon or part of a widespread movement? We shall see.
P.S. I only saw four hawks.