Canadian bird heading back home for summer; Early spring means tree sparrows; Misnamed bird making an appearance
There are Mexican jays and American crows so why can't our neighbors to the north be in possession of a goose? Instead, the possessive form of the proper adjective is nowhere in sight and its name is "Canada goose." Same for its warbler; it's not Canadian, it's a Canada warbler. No one has yet explained this seemingly illogical grammatical imbalance to me.
This crossed my mind last weekend after encountering yet another "American" bird, the American tree sparrow (Spizelloides arborea). Curiously, this is a species that really should have been named "Canadian" sparrow since it breeds across a wide swath of remote northern Canada and Alaska and spends only its winters in the U. S. Early European settlers thought the bird resembled the Eurasian tree sparrow and named the new one "American" to delineate the two; unaware of its remote breeding biology.
Equally misleading is the use of the descriptive, "tree." This is a species that nests on the ground, forages for food on the ground, breeds at or above the treeline in the high latitudes and is about as far removed from being associated with trees than any of our sparrows. Such is the murky arena of common names.
American tree sparrows, to the delight of bird watchers and bird feeders across the northern U. S., are the first sparrow species to begin migrating north in spring. They began showing up in our area within the last 10 days or so. After months of the same old birds in our yards, we now have something new to look at.
Tree sparrows flock in winter in groups of about a dozen. It's uncommon to find a loner as the birds spend the entire season together, usually chatting.
There must be some correlation between flocking behavior and vocalizations because each species that is known to hang out in groups, sings more readily I believe. It must foster flock cohesiveness. Think cedar waxwings, or red crossbills, or even geese; all freely vocalize when together. Tree sparrows are no different as their soft musical twitters accompany their presence everywhere.
I cringe sometimes when I hear someone reporting the first chipping sparrow of the spring, sometime around late March. It likely isn't a chippy but rather an American tree sparrow, which it closely resembles. Tree sparrows also have a rusty cap (although it's pushed forward a bit) and a dark eyeline (rusty rather than a chippy's black) on a gray face, but a closer look reveals subtle differences. A chippy's bill is dark, whereas a tree sparrow's quite petite bill is bi-colored with the top being black, the bottom yellow. Moreover, in the center of a tree sparrow's unstreaked gray breast is a small dark spot, something completely absent on a chipping sparrow.
Taxonomists have given us another wedge between the two species, this one unseen: American tree sparrow used to share its genus—Spizella—with the chipping sparrow. No longer. Recent genetic work has shown the American tree sparrow to be closely related to the fox sparrow (Passerella iliaca) and so has been given in a new genus: Spizelloides, which means "descendent of, or, resembling Spizella."
A small number of these birds winter locally—we find some in almost every year during the Christmas Bird Count-- but most of the population remains farther south. It is during the spring and fall migrations that the birds are most numerous here. I had a most impressive encounter in the fall of 2010, when I came across about 300 American tree sparrows feeding in a weedy area near the Maple River in southwest Cass County. Neither before nor after have I seen anything close to that number.
American tree sparrows are working their way back to the tundra for the summer breeding season which means the other sparrows won't be too far behind. There is much to admire in this handsome little rusty bird which brightens our early spring. I just wish the day would come when we can give it a more fitting common name, like Canadian treeline sparrow. While we're at it, let's get out the eraser and work on the goose and warbler too.