Black-throated Sparrow Life History

Habitat

Habitat Scrub

Black-throated Sparrows use semiopen areas with evenly spaced shrubs and trees that are 3–10 feet tall. They are common in canyons, desert washes, and desert scrub with creosote, ocotillo, cholla, acacia, sagebrush, mesquite, and rabbitbrush. In some parts of their range they occur as high as 7,000 feet elevation in pinyon-juniper forests.

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Food

Food Insects

Black-throated Sparrows are primarily ground foragers, foraging near or under shrubs and cacti. They also glean food from leaves and twigs in shrubs. They mainly eat insects during the breeding season and seeds during the nonbreeding season. Insects include butterfly and moth larvae, mantids, robber flies, dragonflies, and walking sticks.

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Nesting

Nest Placement

Nest Shrub

Female Black-throated Sparrows build nests in shrubs, typically around 1 foot above the ground. Studies in southern New Mexico and central Arizona indicate females often place the nest on the north or east side of the shrub to maximize morning sun and afternoon shade. Nest plants include cholla, brittlebrush, boxthorn, acacia, creosote, mesquite, and other desert shrub and cacti species.

Nest Description

Females collect grasses, plant stems, and rootlets to make a cup-shaped nest. They typically line the nest with finer grasses and animal hair.

Nesting Facts
Clutch Size:2-5 eggs
Number of Broods:1-2 broods
Egg Length:0.6-0.8 in (1.5-2 cm)
Egg Width:0.5-0.6 in (1.2-1.5 cm)
Incubation Period:11-13 days
Nestling Period:9-10 days
Egg Description:

White to bluish white.

Condition at Hatching:

Naked with a sparse cover of down; eyes closed.

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Behavior

Behavior Ground Forager

Black-throated Sparrows hop along the ground searching for insects and seeds. They make short flights low to the ground across desert scrub areas. During the breeding season males and females defend territories and generally don't tolerate intruding birds, especially early in the nesting cycle. Intruders are met with song, fluffed up feathers, and are eventually chased if they don't retreat. After the breeding season they are more tolerant of each other and form small foraging flocks.

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Conservation

Conservation Low Concern

Black-throated Sparrows are common but their populations declined by 42% between 1970 and 2014, according to Partners in Flight. The estimated global breeding population is 51 million. The species rates a 9 out of 20 on the Continental Concern Score, which means it is not on the Partners in Flight Watch List and is a species of low conservation concern. Population changes could be due to drought, Brown-headed Cowbird parasitism, habitat loss due to urbanization, or fire suppression. Under drought conditions some Black-throated Sparrows forgo breeding, reducing the number of young sparrows produced. Brown-headed Cowbirds frequently lay eggs in the nests of Black-throated Sparrows, reducing the likelihood that young sparrows survive. Black-throated Sparrows do not breed in suburban and urban landscapes, so urbanization reduces the amount of habitat available. In areas where fires have been suppressed the vegetation may become too dense for Black-throated Sparrows. When fires do burn, non-native cheatgrass often grows back faster than the native desert scrub vegetation, providing little habitat for Black-throated Sparrows.

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Backyard Tips

Within their range, Black-throated Sparrows sometimes visit backyards to eat seeds such as black oil sunflower. This map shows approximate locations where Project FeederWatch participants have reported Black-throated Sparrows in their backyard counts over the years.

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Credits

Dunne, P. (2006). Pete Dunne's essential field guide companion. Houghton Mifflin Harcourt, New York, USA.

Johnson, M. J., C. Van Riper Iii and K. M. Pearson. 2002. Black-throated Sparrow (Amphispiza bilineata), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Lutmerding, J. A. and A. S. Love (2016). Longevity records of North American birds. Version 2016.1. 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, USA.

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