Perhaps you’ve been noticing some ducks on the marshes as you've traveled over the summer months.
If so, I’d bet that one of the most common ducks you saw was a small duck with a white crescent running down on the front side of its head. That is a male blue-winged teal. And if they haven’t left already, they will soon.
Arthur Cleveland Bent described the fall migration of the blue-winged teal in his Life Histories of Familiar North American Birds:
“As soon as the young are able to fly, or even before that, they begin gathering into flocks preparing for the fall migration, which begins with the first early frosts in August and is mainly accomplished during September, for these delicate birds are very sensitive to the approach of autumn.”
The male blue-winged teal is easily identified by that distinctive white crescent. There is no mistaking it. And the name “blue-wing” comes from the blue patch on the upper front part of the wing (the converts). Like many other ducks, the females are a dull brown.
Blue-winged teal nest over much of North America and are particularly common in the prairie pothole region. They are among the last ducks to arrive in the spring.
The females will check out various potential nesting sites by flying over the area and landing occasionally to get a closer look. She may choose a nesting site in a variety of habitats ranging from upland prairie near a prairie pothole to hayfields, weedy borders of fields, and the like.
After finally making her decision, she will construct a nest in a scrape of ground with dried grass and down before laying 6-14 creamy white eggs which she will incubate for 19-29 days.
Predators get a fair portion of the eggs, and occasionally even the hens. Charles Flugum, an avid birder from southern Minnesota, noted a few blue-wing teal nests over the years on his farm but notes in his book Birding from a Tractor Seat (1973) that one successful blue-wing teal nest was located near a cowpie. Several ground nesting birds are known to nest near cowpies, assumedly because predators avoid the area around a cowpie, or the cowpie masks the scent of the nest. Maybe it is a little of both.
Enjoy seeing the blue-winged teal while you can. They do not like the cold, so as you might expect, they are itching to head south to spend their winter in Latin and South America. But we can look forward to seeing them again next spring.