Bell's Sparrow Life History

Habitat

Habitat ScrubBell’s Sparrows breed in coastal sagebrush, chaparral, and other open, scrubby habitats. In chaparral, they tend toward younger, less dense stands that are growing back from recent fires; they are less common in older, taller stands that have remained unburned. In mountains of Southern California they also occur in big sagebrush (Artemisia tridentata). In the Mojave, Bell’s Sparrows use low scrub including big sagebrush, saltbush, bitterbrush, shadscale, and creosote bush. During migration and winter, Bell’s Sparrows often form loose flocks with other sparrow species, including Sagebrush Sparrows. They use dry shrublands or grasslands, including creosote and saltbush-dominated desert scrub, yucca, honey mesquite, and greasewood.Back to top

Food

Food InsectsBell’s Sparrows eat seeds and insects during the breeding season, taking beetles, grasshoppers, caterpillars, and other insects, plus spiders, seeds, small fruits, and vegetation. During the nonbreeding season, they feed mostly on seeds from grasses, pigweed, and mustard plant.Back to top

Nesting

Nest Placement

Nest ShrubBell’s Sparrow put their nests mainly within shrubs, but also in bunchgrasses and occasionally on the ground under shrubs, including California sagebrush, brittlebush, white sage, black sage, California buckwheat, bush mallow, chamise, cholla, willow, and others.

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.
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Behavior

Behavior Ground ForagerBell’s Sparrows spend most of their time on the ground, foraging under dense shrubs. They tend to run rather than fly, and they often cock their tails or flick them upward. In spring and early summer, males become much more conspicuous when they perch atop shrubs to sing. Almost immediately after finishing a bout of song, they drop directly to the ground and continue foraging, also guarding their mates from advances of other males (a common behavior for many birds). Predators of nests and young include Loggerhead Shrikes, Common Ravens, ground squirrels, and possibly Greater Roadrunners.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 2014. 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. These two species rate an 11 out of 20 on the Continental Concern Score. The Sage Sparrow was a U.S.-Canada Stewardship species. The San Clemente subspecies of Bell's Sparrow is on the 2014 State of the Birds Watch List, which lists species most in danger of extinction without significant conservation action. Bell’s Sparrows depend on fairly open shrubby communities that tend to be maintained by natural fire regimes. Fire suppression can lead to altered, communities with denser shrubs and lower numbers of Bell’s Sparrows. In densely populated Southern California Bell’s Sparrows has also faced habitat loss as suburban development creeps into their attractive coastal sagebrush habitat.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.

North American Bird Conservation Initiative. 2014. The State of the Birds 2014 Report. US Department of Interior, Washington, DC, 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, USA.

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