Thursday, September 9, 2010

The Noisemaker: Killdeer

Famous for its broken wing display, the Killdeer thrives in a human-altered environment. Photo by Doug Brown.

"Killdeer! Killdeer! Dee, deet, dit!” The piteous, shrill wailing call that emanated from the depths of the ink-black sky told the casual listener that somewhere overhead a bird was in the throes of agitation. This might seem to be unusual since most birds do not vocalize after dark lest a nocturnal predator, such as a Great Horned Owl, be alerted to their presence. Not so with the little shorebird currently called a Killdeer for the distress call it uses during the peak of terror, or possibly excitement. The small, plover-like bird is known for its vocal nature and was, in times long ago, called Chattering Plover (1731) and Noisy Plover (1785).

Unlike its plover cousins that inhabit shorelines where they prey on small aquatic prey, you can see a Killdeer without going to the beach. They are quite common in New Mexico throughout the year, frequenting sandbars, mudflats, grazed fields, lawns, golf courses, athletic fields, and parking lots. It is one of the most successful of all shorebirds precisely because of its fondness for human modified habitats and its willingness to nest close to people. For these same reasons; however, they are vulnerable to pesticide poisoning, oil pollution, lawn mowers, and collisions with cars.

Usually they are found near water of some sort, although their idea of adequate water might just be a lawn sprinkler. They thrive in short vegetation averaging about one inch in height. Thus golf courses with abundant sand traps are just about ideal from the bird’s point of view, as they provide three habitat essentials: water, a variety of grasses and grass heights for hunting insects, and sand for nesting.

This small white and tan bird with the black neck band and overly long legs can often be seen in dry, flat landscapes, running across the ground in short spurts, stopping suddenly every once in a while to see if they’ve startled up any delectable insect or earthworm treats. Like many raptors, Killdeer have learned to follows farmers' plows in hopes of retrieving any unearthed worms or insect larvae. Opportunistic, they also have been observed hunting frogs and eating dead minnows.

Killdeer are famous for their broken-wing display where they try to lure predators away from their nest by feigning injury. The bird runs a little, clearly dragging one wing, leading the observer to either view it as an easy meal or as a bird in need of rescuing. As the observer draws closer the bird stays put until the last moment when it runs again, always remaining just out of reach until the bird feels it has drawn the potential predator far enough away from its vulnerable eggs or young.

The broken-wing act does not work against intrusions from cows or cattle, animals that have little interest in a small brown bird. For this type of threat, the Killdeer uses a very different display, fluffing itself up and displaying its tail over its head. Then, it runs straight toward cow/horse animal in an attempt to divert the animal.

Although numbers of Killdeer are likely as high today as at any time in their history due to their fondness for the habitats we create, at one time the population was in serious decline due to hunting pressure. In the mid-1800s, Killdeer were common in markets year-round although, according to Audubon, their flesh was “indifferent” except for fat young birds in autumn. In the South, they were captured with a hook and line baited with a worm. Sometimes, they simply were shot on sight because their noisy warning call alerted other game species of the hunter’s approach.

In the early 1900s, laws were passed by some states to protect Killdeer, but widespread protection finally occurred because of the very low numbers, the fact that the meat was not particularly tasty, and because humans recognized the bird’s beneficial habit of devouring insects. Today, Killdeer are among the most successful of shorebirds, particularly in our human modified habits. We’ve come a long way, from predation to appreciation.