Friday, September 27, 2002
Biodiversity Corner Killdeer
Killdeers are members of the plover family, but unlike most other plovers are often found far from water. They feed mostly on insects, especially beetles, caterpillars, grasshoppers, ants, and true bugs; they are a gardener's friend! They also eat centipedes, spiders, ticks, earthworms, and some weed seeds.
Male Killdeers return to Carlisle from their wintering grounds in late March or early April to establish breeding territories, generally in areas where nesting has been successful in previous years. Several males may vie for the same territory, and will chase and call in an effort to drive other males away. Territories are usually in open areas with little vegetation such as open fields, athletic fields, and even gravel rooftops. A male on territory will give the "killdeer" call from a prominent place on the ground, or while flying above the area. During courtship, both male and female will scrape the ground, making shallow depressions. After mating, the female lays 3-5 eggs, usually 4, in a depression. The eggs are light brown with irregular black or brown spots, and the coloration often blends in well with the background. (A photograph of a Killdeer nest and eggs at Foss Farm gardens appeared in the August 16 issue of the Mosquito.)
Nest sites can be in unexpected places. I remember hearing a Killdeer calling from the roof of an old mill building in Fitchburg, and wondered if there was a nest on the roof. Young Killdeers have been known to jump off rooftops 50 feet above ground and land safely, although in this case they would have landed in a busy parking lot! Several years ago, a Killdeer nested in the middle of a gravel parking lot at Parker River National Wildlife Refuge, and the refuge staff erected a protective fence around the nest.
Last summer, a Killdeer nested successfully in the newly sanded cranberry bog near Curve Street. (Thanks to Mark Duffy for avoiding the nest with his tractor!) The beekeeper who attends the cranberry bog beehives told me that a Killdeer nested in a sandy area between two gravestones in a town cemetery.
The female usually lays one egg per day, and incubation begins after the clutch is complete. Both male and female incubate the eggs, for a total of 24-28 days. After hatching, the baby Killdeers spend only a few hours at most in the nest, and are quickly running around with the adults searching for food. Killdeer young are thus said to be "precocial," a trait which is more common among ground-nesting birds such as plovers and ducks. In contrast to the adult plumage, the downy young Killdeers have only a single breast band.
In the fall, Killdeers migrate south to the southern United States, and even to South America. They usually travel in small flocks, sometimes mixed with other shorebirds. Several years ago, in early October, we observed two large flocks of Killdeer, each about 30 birds, at the Cranberry Bog. The latest date we have seen them in Carlisle is November 5.
Thanks to Phil Brown of Essex, Massachusetts, for permission to use his photograph of a Killdeer family. [We sent an appeal to "massbird," an e-mail list-serve for birders, and received excellent photos from five people. Selecting one for this article was difficult.] For more information on Killdeer behavior, the book by Donald and Lillian Stokes is recommended.
A Guide to Bird Behavior, Volume II, Donald W. and Lillian Q. Stokes, Little, Brown, & Co., 1983.
The Audubon Society Encyclopedia of North American Birds, John K. Terres, Wings Books, 1991.
Submissions for the Biodiversity Corner are encouraged from everyone. Please feel free to write up a species that interests you. The only requirements are that it exists in the wild and was seen in Carlisle. If you have a mystery species and want help with identification, send a photo and some field notes to Kay Fairweather at 392 School Street, Carlisle MA 01741 or to email@example.com
© 2002 The Carlisle Mosquito