Abert's Towhee Life History

Habitat

Abert’s Towhees thrive in native cottonwood-willow riparian forest (also called gallery forest) of the southwestern U.S. and Mexico, which typically has a dense understory of native shrubs. They also live in mesquite woodlands called bosques, especially along the Colorado River. Only about 5% of this habitat remains. In some areas, Abert’s Towhees have begun using other riverside habitats, such as stands of invasive saltcedar (tamarisk). Around cities like Phoenix, Arizona, where exotic plantings are mixed with some native species, Abert’s Towhees have become locally fairly common so long as sufficient understory is present. They also sometimes occur in agricultural areas lined extensively with quailbush.

Food

Year-round, Abert’s Towhees feed mostly on insects, which they find by rummaging on the ground in leaf litter or loose soil, kicking back with both feet simultaneously to uncover prey and also seeds. In summer, insects make up more than 95% of the diet; even in winter insects comprise more than 70% of the diet. Beetles, ants, grasshoppers, cicadas, and caterpillars are the most common prey, and some studies indicate that females take larger prey than males. On rare occasions, Abert’s Towhees hunt insects in bark crevices, creeping and probing like a nuthatch. Plant matter in the diet consists mostly of seeds of grasses, saltbush, and herblike plants in the amaranth family (Amaranthaceae).

Nesting

Nest Placement

Nests are set in areas of dense vegetation, in shrubs (especially boxthorn and Baccharis), mesquite, cottonwood, or Mexican elderberry. In some areas, Abert’s Towhees build nests inside clumps of mistletoe, a dense parasitic plant that remains green year-round. Nests are mostly located 5–7 feet above the ground, but the height varies locally, depending partly on where the vegetation has adequate foliage to conceal and shade the nest.

Nest Description

The nest is a bulky cup made of the leaves and bark of mesquite, cottonwood, and willow, leaves of saltcedar, saltbush, inkweed, and arrowweed, along with some grasses. Nests average 4 inches tall by 5.4 inches across, with the cup itself 3 inches across and 1.6 inches deep.

Nesting Facts

Behavior

Abert’s Towhees spend most of the day feeding on the ground, where they seek insects and seeds. Foraging birds are normally found inside the understory, where they employ a “double-scratch” method to uncover food in the leaf litter, hopping forward, then rapidly scratching both feet backwards to move the leaves aside. They feed mostly in the morning and very late afternoon. During the heat of midday and afternoon, they rest in dense thickets. Abert’s Towhees take dust baths, flicking dust onto the spread wings and tail to reduce mites and other parasites. Although not as conspicuous as many species in its desert environment, Abert’s Towhees can be quite bold and aggressive, clashing with others of its species at territorial boundaries or at food or water sources. They also displace other sparrows, towhees, and cardinals from feeding areas, chasing them or spreading the body and tail feathers in a threat display. Pairs maintain permanent territories of about 3–5 acres, with males singing and calling frequently and often chasing rival males in flight. Females tend to chase rivals more on the ground. To maintain pair bonds, the male and female face each other and perform a “squeal duet,” a rapid series of scratchy notes. Pairs are less territorial when not breeding, mostly in the winter, but occasionally still duet. Pairs typically remain together for life.

Conservation

Abert’s Towhees are fairly common within their small range, and their numbers have increased by an estimated 20% since 1970, according to Partners in Flight. The estimated global breeding population is 840,000. They rate a 12 out of 20 on the Continental Concern Score and are not on the Watch List, indicating they are a species of low conservation concern. Although they’ve seen recent increases, Abert’s Towhee numbers are lower than in previous centuries as up to 95% of their original habitat along Southwestern rivers has been converted to agriculture or development, or degraded. Suburban habitats and invasive saltcedar (tamarisk) stands offer some new habitat for Abert’s Towhees. Habitat protection and removal of grazing to benefit endangered southwestern Willow Flycatchers may also benefit Abert’s Towhees.

Credits

Lutmerding, J. A., and A. S. Love (2017). Longevity records of North American birds. Version 2017.1. Patuxent Wildlife Research Center, Bird Banding Laboratory, Laurel, MD, USA.

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

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.

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

Tweit, Robert C. and D. M. Finch. (1994). Abert's Towhee (Melozone aberti), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

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