LeConte's Thrasher Life History

Habitat

LeConte’s Thrashers live in low, sandy, open deserts that are home to few other bird species. Over most of their range, saltbush, shadscale, cholla cactus, creosote, yucca, mesquite, and ocotillo are common plants, but they are usually sparsely distributed in these mostly flat or rolling landscapes. LeConte’s Thrashers generally do not inhabit steep-sided canyons, preferring small arroyos, open flats, or dunes. Rainfall and flowing streams are rare in these deserts, and air temperatures are among the highest recorded on earth.

Food

LeConte’s Thrashers eat insects and other arthropods, from which they also get most of the water in their diet. They forage in areas of leaf litter by striking away the material with strong swipes of the large bill. They also use the bill to excavate pits in the ground, up to 5 inches deep, and can flip over rocks and debris of considerable size and weight, using their strong legs and tail for leverage and balance. LeConte’s Thrashers also chase prey on foot, including small vertebrates and insects, and they pick or glean insect prey off low vegetation as well. They eat grasshoppers, darkling beetles, weevils, caterpillars, ants, scorpions, spiders, lizards, snakes, and bird eggs. They also consume seeds of mesquite, stork’s bill, and other desert plants.

Nesting

Nest Placement

Females select the nest site, usually a spot concealed within cholla cactus or thorny desert shrub, often in a shady spot such as the edge of a dry streambed, about 3 feet above the ground.

Nest Description

Male and female build a bulky stick and twig nest lined with smaller twigs, grasses, and rootlets and finished with still finer materials in a third layer: these materials include fuzzy plant seeds, leaves, flowers, and sometimes human-made products such as cotton material. The interior cup of the nest averages about 3.5 inches across and and 3.1 inches deep; the more bulky outermost layer varies considerably in dimensions. Pairs sometimes reuse old nests.

Nesting Facts

Behavior

Breeding season begins in December, a mercifully cool time of year in the deserts. Males perch prominently on shrubs and trees to sing, marking territory and advertising for mates. Males perform brief courtship displays to females that involve raising the bill, lowering the tail, bowing, and pecking at the ground. A receptive female might then raise her head and tail, droop and flutter her wings, and give calls that sound like a chick begging. Members of a pair sometimes perform these displays after they have driven intruders of their species out of the territory. Although LeConte’s Thrashers are socially monogamous for the most part, and some pairs remain together year-round for several years in a row, one study revealed that two males had two mates each. Both male and female share incubating and chick-rearing duties. The dispersal of young from their parents’ territory has not been the subject of a study; the species is not migratory but has turned up in places where the species does not breed.

Conservation

LeConte's Thrashers are inconspicuous birds that live in remote, forbidding habitats, making it difficult to track their population trends with precision. The North American Breeding Bird Survey reports a possible decline of 1.99% per year between 1968 and 2015, but notes low statistical confidence in that estimate. If correct, that annual decline would correspond to a cumulative decline of about 62% during that time. Partners in Flight estimates a global breeding population of 71,000 birds, with about 64,000 of those in the U.S. Partners in Flight rates the species a 17 out of 20 on the Continental Concern Score, and includes it on the Red Watch List. Destruction of its desert habitat by development, grazing, off-road vehicles, and fire has been the cause of its decline.

Credits

Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Rosenberg, K. V., J. A. Kennedy, R. Dettmers, R. P. Ford, D. Reynolds, J. D. Alexander, C. J. Beardmore, P. J. Blancher, R. E. Bogart, G. S. Butcher, A. F. Camfield, A. Couturier, D. W. Demarest, W. E. Easton, J. J. Giocomo, R. H. Keller, A. E. Mini, A. O. Panjabi, D. N. Pashley, T. D. Rich, J. M Ruth, H. Stabins, J. Stanton, and T. Will (2016). Partners in Flight Landbird Conservation Plan: 2016 Revision of Canada and Continental United States. Partners in Flight Science Committee.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sheppard, Jay M. (1996). LeConte's Thrasher (Toxostoma lecontei), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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