Sagebrush Sparrow Life History

Habitat

Habitat ScrubSagebrush Sparrows breed in shrubsteppe habitats consisting of shrubs up to about 6 feet tall, especially big sagebrush (Artemisia tridentata) as well as saltbush, rabbitbrush, shadscale, and bitterbrush. They are mostly found below about 5,600 feet elevation. They also nest in mixed sagebrush-juniper habitat that borders open sagebrush steppe. During migration and winter, Sagebrush Sparrows often congregate in loose flocks with other sparrow species and use dry shrublands or grasslands, including creosote and saltbush-dominated desert scrub, yucca, honey mesquite, and greasewood.Back to top

Food

Food InsectsOmnivorous and opportunistic during the breeding season, taking beetles, grasshoppers and other insects, spiders, seeds, small fruits, and succulent vegetation. During the nonbreeding season, the Sagebrush Sparrow feeds mostly on seeds.Back to top

Nesting

Nest Placement

Nest ShrubSagebrush Sparrows put their nests mainly within shrubs, but also in bunchgrasses and occasionally on the ground under shrubs. They prefer taller shrubs with larger canopies, providing more cover. Ground nests benefit from warmth early on in the breeding season, but nests in shrub canopies benefit from greater air circulation later on, as the summer grows hotter. Sagebrush Sparrows are closely associated with big sagebrush, but may choose other shrub species in areas with higher shrub diversity. They tend to build their nests under densest cover within the shrub, and nearer the main stem than the outer edges. They also tend to avoid southwest aspects, possibly because of exposure to the afternoon sun.

Nest Description

The female builds the nest, which is an open cup of twigs and coarse grasses, lined with finer grasses and thin bark, and finally feathers, wool, and animal hair. Nests measure about 4 inches across, and the inner cup is typically about 2.5 inches across and 2 inches deep.

Nesting Facts
Clutch Size:1-4 eggs
Number of Broods:1-3 broods
Egg Length:0.7-0.8 in (1.8-2 cm)
Egg Width:0.6-0.6 in (1.4-1.5 cm)
Incubation Period:10-16 days
Nestling Period:9-10 days
Egg Description:Pale blue or bluish white speckled with brownish, ruddy, or black.
Condition at Hatching:Skin orange-yellow, with sparse patches of down.
Back to top

Behavior

Behavior Ground ForagerSagebrush Sparrows tend to be inconspicuous, and spend most of their time running and foraging under dense shrubs, tail cocked upward and flicking. During territory establishment and breeding in spring and early summer, males perch atop shrubs to sing. Almost immediately after finishing a bout of song, they drop directly to the ground and continue foraging or protecting their mates from advances of other males (a common behavior for many birds, known as mate-guarding). Unlike most migratory songbirds, Sagebrush Sparrows often arrive on the breeding grounds already paired. The males don’t start vigorous singing for a few days after arrival; the songs may function more in territory defense than mate attraction by this stage. Females build the nests while males continue singing. Sagebrush Sparrows frequently raise two broods (occasionally one, and rarely three), and juveniles from first clutches form small flocks in July, to be joined in late August by second-clutch juveniles and adults. Sagebrush Sparrows on migration form small, mixed species flocks with other sparrows. Back to top

Conservation

Conservation Low ConcernBecause of the very recent taxonomic split from Bell's Sparrow, the latest population trends from the North American Breeding Bird Survey are only for "Sage Sparrow," which included both Bell's Sparrow and Sagebrush Sparrow. These trends indicate that Sage Sparrow populations were stable, with a possible small decline, between 1966 and 2015. Partners in Flight estimates the combined breeding population of Sagebrush Sparrow and the closely related Bell’s Sparrow at 4 million, with 95% spending part of the year in the U.S., and 25% wintering in Mexico. Sagebrush Sparrow rates a 12 out of 20 on the Continental Concern Score. It is not on the 2016 State of North America's Birds' Watch List. Sagebrush Sparrows depend on sagebrush and will abandon habitats that become altered by cheatgrass invasion, sagebrush and other shrub removal, or overgrazing of native forbs by livestock. Habitat fragmentation can expose Sagebrush Sparrows to Brown-headed Cowbird parasitism.Back to top

Credits

Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.

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, USA.

Back to top