Charadrius vociferus
Of all our shorebirds, none is so well known as the Kilideer. Its familiarity is a function of its
choice of habitats, its onomatopoetic killdee calls, its so ostentatious broken-wing distraction display, and its ubiquity. In the catalog of human-bird interactions, the Killdeer must be counted among the winners. Unlike many species, there are probably more Killdeer in Texas today than ever. This is a bird that has benefited from many of the human actions that have been detrimental to other species: graveled road shoulders, parking lots, and even graveled rooftops are favored nesting sites; golf courses, crop lands, heavily grazed pastures and feedlots, and even fresh clearcuts provide for feeding and nesting. Suburbia, irrigation, and stock tanks in west Texas have opened up vast areas to Killdeer.
The Killdeer is not without its problems, however. Pesticides, other chemicals, and cats are among the more serious human-provided threats to the birds year round. As a result of disturbance at the nest, a pair may make as many as six nesting attempts in a season in order to successfully raise at least one chick.
DISTRIBUTION: TBBA data suggest a more uniform distribution of Kilideer in east Texas, hence, as evidenced by Breeding Bird Survey (BBS) data (Sauer et al. 2005), a greater abundance than elsewhere in the state. There is a gradual diminishing of populations to the west, and larger populations in suburban areas. The key is habitat availability. With increasing aridity to the west, the species becomes increasingly limited to riparian and irrigated areas, but this is a species that might be expected to turn up wherever suitable habitat can be found. Comparison of the TBBA map with that of Oberholser (1974) shows a remarkable similarity — a gradient of decreasing presence from east Texas to the Rio Grande and western mountains. There are notable areas where the birds are absent in the heavily forested region of east Texas, and a relatively more uniform presence along the coast. The latter may be more a preference for mowed, clipped, graveled, and irrigated suburbia than for natural coastal habitats, although the natural coastal habitats are important wintering habitat for the species. Because of human modification of habitats, it is likely that Killdeer nest in every Texas county and most TBBA quads.
SEASONAL OCCURRENCE: Kilideer occur throughout Texas throughout the year, although their populations swell in late summer and early fall with recent fledglings and northern migrants and diminish by early March as winter visitors return to more northern breeding areas, Killdeer in the southern United States tend to be resident and at least some maintain territories and pair bonds year round (Jackson and Jackson 2000). Winter migrants are often found in small flocks in feeding areas, only occasionally joined by resident pairs. Foods probably vary somewhat seasonally, including primarily small invertebrates such as earthworms and grasshoppers, but opportunistically including such things as small frogs and dead fishes. Killdeer courtship activities begin in mid-February in Texas and the first nests have eggs by early March. Because of the warm climate, Killdeer have a long breeding season in Texas and they often have several nest attempts per year. In Mississippi, Killdeer have successfully hatched young as late as mid-November (Jackson and Jackson 2000) and it is likely that such late nesting may occur in southern Texas as well. Extreme nesting dates for Dallas County in north Texas were 6 March (3 eggs) and 18 August (chicks), with a peak of nesting in mid-April (Pulich 1988). Extreme nesting dates included in the TBBA files among 59 records with nest dates were 20 March and I 8 July. Of the TBBA nest records for Killdeer, 27 (46%) were in May. However interpretation of these dates must be cautious because TBBA observers were more likely to be looking for nests in May.
BREEDING HABITAT: For nesting, suitable habitat is almost anywhere that water and relatively bare “ground” can be found. In rural areas heavily grazed pastures and gravel roadsides are favored. In urban areas, gravel parking lots and flat gravel rooftops have become common nesting sites, although the latter can be lethal for eggs and chicks because of summer temperatures and inability of chicks to leave some roofs. Chicks are not fed by their parents and must get to an area where small invertebrates are readily available. They easily survive leaps from low roofs, but a parapet around the edge of the roof may prevent them from leaving. While not tied to aquatics habitats in the way that other shorebirds are, wet soil environments produce the invertebrate diversity and abundance that provides protein for growing chicks. Almost as soon as the down of the last-hatched chick dries, parent Killdeer begin leading their brood to streamside, lakeside, drainage ditch-side, or simply wet ground.
STATUS: Killdeer are a common breeding species in open habitats throughout eastern and coastal Texas, becoming less common in more arid western areas. Numbers have almost certainly increased as a result of habitat changes associated with human population growth, however,BBS data (Sauer et a!. 2005) suggest a slight overall population decline since the mid-1970s, including a significant decline in Texas over the period 1966-2004. Although not threatened as a species, Killdeer are vulnerable to many hazards in the human environments that attract them: vehicle traffic, roadside and agricultural spraying, and oil and chemical contaminants in industrial areas. In urban and suburban environments their eggs and chicks are vulnerable to cats, dogs, and the curiosity of children.
Text by Jerome A. Jackson (Posted with updates 2007)
Literature cited.
Jackson, B. J. S., and J. A. Jackson. 2000. Killdeer (Charadrius vociferus). In The Birds of North America No. 517 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
Oberholser, H. C. 1974. The bird life of Texas. Univ. Texas Press, Austin, Texas.
Pulich, W.M. 1988. The birds of north central Texas. Texas A&M University Press, College
Station.
Sauer, J. R., J. E. Hines, and J. Fallon. 2005. The North American Breeding Bird Survey, results and analysis 1966-2005. Version 6.2 2006. USGS Patuxent Wildlife Research Center, Laurel MD < http://www.mbr-pwrc.usgs.gov/bbs>