DOOR TO NATURE: The American Kestrel

It is the peak of the autumn migration and there are many small birds along the shoulders of open country roads. Several species of thrushes have been seen at the bird baths in recent weeks and many warblers are moving through the woods. A female yellow-rumped warbler drank at the bath yesterday.

The eastern kingbirds, swallows and quite a few other species that nested here have left for the South. American goldfinches completed their late breeding season and may still be in post-nuptial molt, but are rarely seen at the feeders now. They change into their drab winter plumage and will stay here for the whole year.

Early October can be an unusually good time for birdwatching. Hawks and Canada geese will continue to move through the area during the month, especially on days when the air pressure and north winds produce the best flying conditions.

The giant race of Canada geese that nested in this region have developed flocks and, being creatures of habit, will fly regularly between their daytime feeding fields and resting areas at night. You can expect to see skeins of up to 50 geese fly over the farmlands and perhaps head for the wilderness of Lost Lake where they’ll spend the night.

Under ordinary weather conditions these giant geese will remain in our area until well into early winter before heading southward, but no farther than is necessary to find food. Essentially, like their smaller cousins which nest further north and migrate to the South for the winter, the “giants” are thought of as non-migratory birds. Given a mild winter with little snow, they may remain here, especially if the Lake Michigan and Green Bay waters remain open.

One of our favorite birds that lingers in the area until early December or even later is the American kestrel. During winters with little snow cover these birds are often seen on power lines along the highways. 

The American kestrel, formerly called the sparrow hawk, is the smallest of the seven falcons found in North America. Many people are familiar with the large peregrine falcons because of the publicity their successful rehabilitation program has received. The biggest species in this group is the gyrfalcon of the Arctic tundra.

Falcons are beautiful streamlined birds designed in nature to be strong, swift fliers and divers (in the air). They have broad, relatively powerful shoulders that taper back to long pointed wings and medium-long tapered tails. Their wings resemble those of mourning doves in flight, and are described as being “high speed” wings.

Their bullet-like heads and short necks contribute to their sleek shape. Typically, they have strongly hooked beaks that are conspicuously toothed, wonderfully adapted to tearing into their prey. Their taloned feet also help them catch and hold their prey. One could say they are swift and “talonted” pursuers of grasshoppers, crickets, mice, voles and small birds of the open countryside.

A good field mark to notice on both male and females is the double- black, vertical stripes on the sides of their white faces. Both also have a rufous-red back and tail, somewhat darker and more distinct on the male.

The male has blue-gray wings while the female has larger brown wings. In general, the females are about one-third larger overall than the males. This is true of most birds of prey.

Even though the kestrel is smaller than the sharp-shinned hawk, smallest of all North American hawks, its longer pointed wings make it appear larger. Wings of the sharp-shinned hawk are shorter and have rounded tips.

Kestrels fly with rapid wing beats and short glides, often circling and hovering over a field as they search for their prey. They live mainly along woodland borders, open fields and pastures with scattered trees. Most of their hunting is done in the early morning and late afternoon.

These nine-inch-long falcons breed throughout our country and across most of southern Canada. They nest in tree cavities, old woodpecker holes and man-made nest boxes. They lay an average four-to-five eggs and, in the North, they have one brood, perhaps two in the South. Those that do migrate often spend the winter as far south as Panama.

Include among your winter projects the simple construction of a few kestrel nest boxes. The floor size is eight-by-eight inches, and the depth of the box 12 to 15 inches. The three-inch-diameter entrance hole should be placed about three inches from the top. Make a hinged side so it can be easily cleaned out and place a four-inch layer of clean, dry sawdust or fine wood shavings in the box by early March.

We placed a kestrel box 12 feet above the ground in a large tree at the edge of our wooded land years ago, and they accepted it quickly. It is pure joy to help these sleek fliers and know your contribution matters.