Black-throated Gray Warbler Life History

Habitat

Habitat Forests

Black-throated Gray Warblers breed in open pine forests, pine-oak woodlands, and pinyon-juniper forests with a brushy understory. During migration and on the wintering grounds, they use similar habitats in addition to woodlands, scrub, and thickets.

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Food

Food Insects

Black-throated Gray Warblers primarily eat insects that they pluck from trees and shrubs. They tend to forage in the lower to middle levels of the forest, moving with slow, deliberate hops while looking around for insects.

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Nesting

Nest Placement

Nest Tree

Black-throated Gray Warblers typically nest on a horizontal branch or fork in firs, oaks, or pinyon pines. The nest is generally built 3 to 35 feet above the ground.

Nest Description

Females weave together bark, grasses, and mosses into a deep and somewhat bulky cup and line it with feathers.

Nesting Facts
Clutch Size:3-5 eggs
Number of Broods:1-2 broods
Egg Length:0.6-0.8 in (1.5-1.9 cm)
Egg Width:0.5-0.6 in (1.2-1.4 cm)
Egg Description:

Cream-colored with brownish speckles and dots.

Condition at Hatching:

Naked with eyes closed.

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Behavior

Behavior Foliage Gleaner

Black-throated Gray Warblers forage with slower movements than some warblers. They hop between branches in the lower and middle levels of open coniferous forests plucking caterpillars from leaves. Males sing a buzzy song from prominent perches to mark their territory and often chase away birds that enter. They spend time in pairs during the breeding season, but join mixed-species flocks during migration and on the wintering grounds. Female Brown-headed Cowbirds sometimes lay eggs in the nests of Black-throated Gray Warblers, a behavior known as nest parasitism, in which the hosts (in this case the Black-throated Gray Warbler) raise cowbird young instead of their own.

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Conservation

Conservation Low Concern

Black-throated Gray Warblers are common, but their populations declined by 49% between 1970 and 2014, according to Partners in Flight. The estimated global breeding population is 2.9 million. The species rates a 13 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.

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Credits

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

Guzy, Michael J. and Peter E. Lowther. 2012. Black-throated Gray Warbler (Setophaga nigrescens), 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.

Stephenson, T. and S. Whittle (2013). The Warbler Guide. Princeton University Press, New Jersey, USA. 

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