Some migrants pass through unseen and unsung

Body: 

Every autumn we're reminded of just how fleeting are the events unique to this season. Most obvious are the changes in vegetation, as maples turn from familiar green to a dazzling range of oranges and reds, birch and aspen to yellow-gold, while other trees and shrubs fill in the rest of the tones in Nature's palette of colors.

Migration is as dependable and inevitable as the changing colors, as birds that are not fitted for brutal northern winters retrace the northward routes of spring on their way south to wintering grounds. There, the lifestyle they're adapted to will go on, there spending the intervening months rebuilding bodily reserves they'll need when the cycle repeats itself all over again.

We're most familiar with the showy among these migrants. Waterfowl, the ducks and geese, are prime examples. Some are gaudier in their coloration than the showiest maple tree. Wood ducks are the best example, but many are strikingly handsome. Not only are waterfowl beautiful, but they're hard to miss in their wedges and V-formations winging their way across autumn skies. Some — like geese and swans — announce their passage with honking and trumpeting that can be heard when they're mere specks high above the earth.

Hawks and owls, solitary during the breeding and summer seasons, put on a dramatic aerial show when it's time for them to leave the North for the winter. Hawk Ridge near Duluth is a choke-point in raptor migration, famous for the thousands of hawks and owls that concentrate and fly over the headlands at the western end of Lake Superior. This is because raptors prefer overland migration to crossing large bodies of water.

The exodus begins as early as August and continues as late as December. Sharp-shinned and broad-winged hawks, red-tailed and rough-legged hawks, goshawks, eagles and the migratory owls, come through in the hundreds and thousands. Over the last two decades, an average of 75,000 raptors per year have been counted passing over Hawk Ridge during the autumn migration.

But there are many migrants that attract far less attention. On a recent morning, reading the day's news by the kitchen window over a second cup of coffee, a loose flock of small, brownish birds darted into view and landed in the carpet of leaves and bark chips between the ferns, the hostas and other ornamentals best known to the family's head gardener (my spouse). They were scratching and scuffling, both feet kicking backward at the same time, propelling the bird into a little vertical hop. I interpreted this scratching as meant to reveal insects hiding there in the litter, or to uncover edible seeds that might otherwise escape notice. Feeding was clearly the point of the routine.

I'm not a serious birder of the sort that keeps a "life list," or makes pilgrimages when the whereabouts of a rare or uncommon bird is reported. But I do keep a good field guide in the family room, beyond whose windows are our bird feeders and the fountain that doubles as a bird bath. If an interesting or unusual bird visits the backyard, I want to scope it out with the book while I still remember its distinguishing features.

The smaller the bird, the more difficult to see those features, so it's a good idea to keep a pair of binoculars handy. I have a habit of leaving mine in the car, or in a gear bag that I take fishing or hunting, so too often they're beyond reach when I need them in the backyard. Fortunately, these active little birds were close enough to see some clues to their identity. Often it's the male that wears the more visible giveaways. Immature songbirds and females often lack some of the most colorful and distinct features.

And so it was with these visitors. Their predominantly brown tones made the sparrow family a good guess. But the variety of North American sparrows is legion, and many look very similar. What stood out among these? Of the handful there in the garden scratching for a meal, several were boldly colored, with striped white and black cap, a white throat patch and a smaller yellow spot over the eye.

Though I've ID'd these birds before, I flipped through the bird guide to confirm what I guessed were white-throated sparrows. It would be fitting for them to show up in numbers now. They breed to the north of us, mostly in Canada, and we generally see and hear them only in spring and fall when passing through. White-throats have one of the most distinctive and melodic of bird songs. I've most often heard them in spring when they have courtship on their mind, typically in thickly-forested country where I find myself along a trout stream.

Consistent with our human-centric ways, we use words to interpret the sounds birds make. "Whip-poor-Will" is a classic interpretation of a bird's call, and we've given the bird that very name. The white-throated sparrow's song begins with a low note, then a high note, followed by series of rapid low notes. Some way it's singing "pure...sweet...Canada-Canada-Canada." Others say it's "poor...sam...peabody-peabody-peabody." Given the wild and pristine places where I've most often heard it, I'd lean toward the former.

Soon these white-throats will be beyond Minnesota's borders, bound for the Gulf Coast or northern Mexico. In a normal year, the prospect of wintering in these balmy parts of the world might be cause for jealousy. Given the abundance of tropical storms and hurricanes so far, this might not be the year.