Curve-billed Thrasher, Toxostoma curvirostre

Curve-billed Thrasher, Toxostoma curvirostre maculatum. Photographs taken within a residential community in Alamos, Sonora, January 2018 and 2019. Photographs and identification courtesy of David F Smith, Alamos, Sonora.

Curve-billed Thrasher, Toxostoma curvirostre maculatum. Photograph taken within a residential community in Hereford, Arizona, November 2020. Photograph and identification courtesy of Bob Behrstock, Sierra Vista, Arizona (naturewideimages.com).

Background and Identification

The Curve-billed Thrasher, Toxostoma curvirostre maculatum, is one of seven subspecies of Curve-billed Thrasher, and all seven are permanent residents of Mexico. They are a member of the Mimidae Family of Mockingbirds and Thrashers, which has thirty-four members in ten genera, and one of as ten global species of the Toxostoma Genus. They are known in Mexico as Cuitlacoche de Pico Curvo.

The Curve-bill Thrasher is similar in stature to the American Robin, but slimmer, heavy-legged, with a slightly rounded long tail with a blunt tip. Their overall plumage color is grayish-brown with a white throat white. Their underparts are rusty-brown and deepen in color on the rump and outwebs of the secondaries. They have brown spots across the chest and there is a rusty tinge across the breast, along the sides, and over the anal region. Their bill is long, slender, blackish, and decurved. Their wings are brown with broad white tips.

Habitat and Geographical Range

The Curve-billed Thrasher is found within semi-open arid habitats with cacti and shrubs of the coastal plain and foothills. They are found at elevations below 1,400 m (4,600 feet). They are ground foragers that feed primarily on insects and seasonal berries, cacti fruit and seeds. They are non-migratory with life spans of up to eleven years. They have a loud, distinctive double whistle. The Curved-bill Thrasher is poorly studied, and their behavioral patterns are not poorly documented.

The Curve-billed Thrasher is found throughout northern Mexico and in the interior away from the coasts extending as far south as Mexico City. The maculatum subspecies is found in western Mexico within the Pacific Slope of southwest Chihuahua and Sonora.

Common Misidentifications

The Curve-billed Thrasher is difficult to distinguish from Bendire’s Thrasher, Toxostoma bendirei, and the Crissal Thrasher, Toxostoma crissale. The Bendire’s Thrasher has a straighter bill and less prominent spotting on the chest compared to the Curve-billed Thrasher. The Crissal Thrasher has very similar size and coloration to the Curve-billed, but the Crissal Thrasher has a much more pronounced cinnamon-colored undertail.

Conservation Status

From a conservation perspective the Curve-billed Thrasher is currently considered to be of Least Concern with stable widely distributed populations. Their populations are adversely affected by the conversion of grass and woodland to Buffel Grass, Pennisetum cituare, in Sonora. This grass is highly invasive and has become a monoculture in many areas.