Le Conte's Thrasher was discovered by Dr. John Le Conte, a Boston entomologist, in late 1850 or early 1851 in Yuma County, Arizona ( Phillips 1964b , Phillips 1986a ). This discovery and its description might never have been reported to the world ( Lawrence 1851 ) had not Dr. Le Conte narrowly escaped a deadly Indian raid a few months later ( Stratton 1857 ). Until about 1882, "LeConte's Mockingbird" was known from only a handful of specimens and additional observations ( Stephens 1884 ). Over the next thirty years, many hundreds of observations and specimens were obtained, as well as the first nest ( Holterhoff 1883 ).
Le Conte's Thrasher remains an uncommon resident of the deserts of the American Southwest 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 it; 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. 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 adults per square kilometer. In some parts of its range, this thrasher has lost extensive habitat to development; irrigated lawns, groves, and 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 = 335 banded birds, including 90 adults) near Maricopa in the San Joaquin Valley of 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 the examination of more than 600 specimens and record cards from more than 450 egg sets from major collections around the country ( Sheppard 1970 , Sheppard 1973 , JMS).