LeConte's Thrasher was discovered by Dr. John LeConte, a Boston entomologist, in Yuma County, Arizona, in late 1850 or early 1851 (1, 2). Originally named "LeConte's Mocking Bird (3)," the species was known from only a handful of specimens and additional observations until about 1882 (4), with the first nest being described in 1883 (5). Over the ensuing 30 years, many hundreds of observations and specimens were obtained throughout its range.
LeConte's Thrasher remains an uncommon resident of the deserts of the southwestern United States and northwestern Mexico, where it inhabits some desolate environments. Water may be present for only a few days each year, and even then the bird rarely drinks—this species is a true xerophile. It feeds almost exclusively on arthropods that it digs from the litter under desert shrubs, and its normal mode of locomotion is to run between shrubs in the fashion of a Greater Roadrunner (Geococcyx californianus). With its rather plain, sandy coloration, this thrasher blends into the usually dry desert vegetation and pale ground surface, although while running it often holds its contrasting, nearly black, tail cocked high over its back.
Regular singing starts in early fall and peaks in December and January, and egg-laying begins in February and extends through May and early June. The species has no migration or seasonal movements, and pairs remain together year-round. Even in the most populated habitats, densities may reach only 10–12 adults per square kilometer. In some parts of its range, the LeConte's Thrasher has lost extensive habitat to development—irrigated lawns, groves, and agricultural fields are not compatible with its need for desert vegetation.
Unless otherwise indicated, the major source of information in this account is an intensive study of this species conducted between 1968 and 1971 by the author and involving a color-banded population of approximately 35 pairs (n = 353 banded birds, including ~90 adults) near Maricopa in the San Joaquin Valley of southwestern Kern County, California. The study included about 2,000 field hours at Maricopa and about 1,000 field hours elsewhere in the species' U.S. range, as well as examination of more than 600 specimens and ~700 egg-set and nest records from major collections and institutions around the United States (6, 7, 8).