Introduction

Abert’s Towhee inhabits dense brush and woodlands along Sonoran Desert rivers and streams in Arizona and surrounding states. Spencer Baird described this species in 1852 (Am. Ornithol. Union 1983) and named it for Lt. James William Abert, U.S. Army (1820–1897), who obtained the specimen as a result of a survey of New Mexico at the end of the Mexican War. Abert, a West Point graduate, served in the Topographical Engineers and retired from the Army after the Civil War with the rank of Lt. Colonel (Mearns and Mearns 1992).

Because this nonmigratory towhee spends most of its life on a permanent territory concealed by dense shrubs, it is thought to be secretive and is most often detected by its call notes. In interactions with other birds, however, it is bold and aggressive and where it finds suitable habitat in suburban environments it is often oblivious of humans.

Unlike the song of the Rufous-sided Towhee (Pipilo erythrophthalmus), the song of this towhee is rarely heard. The species’ most characteristic vocalization is the squeal duet given simultaneously by both sexes upon reunion—a call used most often during the long breeding season to promote and maintain a close pair bond. This close and prolonged pair bond allows Abert’s Towhee to initiate nesting rapidly in response to changes in weather or food supply, to minimize the nesting period, and to renest quickly after nest failure in an environment where rates of predation and parasitism are high.

Abert’s Towhee has heavy legs typical of a ground forager, and it spends almost all of the nonbreeding season scratching for insects and seeds or perching in low shrubs or tree branches. Its flights, which account for less than 5% of its daylight hours, are short and low, usually to perch sites, including wall tops in suburban habitats.

After an extended period of dry weather, rain during the breeding season can produce a peak in nesting activity within two weeks. The extended breeding season and tight pair bond enable some Abert’s Towhees to produce two broods a year in an inhospitable environment, although as many as six nest attempts may be required. A female can lay the first egg of a new clutch one week after the loss of a nest. Cowbird parasitism reduces towhee reproductive success, but few young cowbirds are raised because some towhees abandon nests with cowbird eggs and because cowbird nestlings are generally much smaller then their towhee nestmates.

The preferred streamside habitat of Abert’s Towhee—the brushy understory of cottonwood (Populus fremonti)-willow (Salix goodingii) gallery forests and mesquite (Prosopis spp.) bosques—has been cleared and otherwise altered by people, starting with Native Americans, primarily for agricultural fields and cattle grazing. Although this towhee has adapted to some urban and shrubland habitats created by people, including irrigation ditches, these do not equal the extent of habitat lost.