Common Yellowthroat Life History

Habitat

Habitat ScrubCommon Yellowthroats live in thick, tangled vegetation in a wide range of habitats—from wetlands to prairies to pine forests—across North America. Their breeding range stretches across most of the United States, the Canadian provinces, and western Mexico. Yellowthroats are most common in wet areas, which tend to have dense vegetation low to the ground, ideal for skulking and building hidden nests. But they are also found in dry upland pine forests, palmetto thickets, drainage ditches, hedgerows, orchards, fields, burned-over oak forests, shrub-covered hillsides, river edges, and disturbed sites. They winter in similar habitats with dense vegetation in the southern United States, Mexico, Central America, and the Caribbean.Back to top

Food

Food InsectsCommon Yellowthroats forage on or near the ground, eating insects and spiders from leaves, bark, branches, flowers, or fruit in low vegetation. Their diet includes bugs, flies, beetles, ants, termites, bees, wasps, grasshoppers, dragonflies, damselflies, moths, butterflies, caterpillars, and other larvae. Though they mostly glean their food while perched, they may sally out from a perch to catch prey. Like many birds, Common Yellowthroats also eat grit, which possibly helps them digest food or adds minerals to their diet.Back to top

Nesting

Nest Placement

Nest ShrubThe female selects a nest site, which is usually on or near the ground and supported by sedges, grasses, reeds, cattails, briars, skunk cabbage, or other low plants. Nests in marshy areas are usually higher off the ground, where they are safer from flooding. On rare occasions the female may build in vegetation growing out of the water.

Nest Description

The female builds her well-concealed nest in 4-5 days (sometimes 2-3 days later in the season). She starts by building a platform of grasses and leaves and gradually weaves a loose, bulky outer cup of grasses and sedges. She adds smaller materials toward the center, sometimes in distinct layers. The outside of the nest averages 3.5 inches wide and 3 inches deep, while the inner cup averages 2.2 inches wide and 1.8 inches deep. Sometimes a Common Yellowthroat nest has a roof, like the nest of an Ovenbird.

Nesting Facts
Clutch Size:1-6 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:12 days
Nestling Period:12 days
Egg Description:White with markings of gray, lilac, reddish-brown, or black.
Condition at Hatching:Helpless, with dark orange skin and wisps of grayish down.
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Behavior

Behavior Foliage GleanerMales arrive first on breeding grounds in the spring and begin defending territories, fighting more intensely when the females arrive. The black mask is an important signal in male fighting: when researchers added a black paper mask to a stuffed female, males started attacking the stuffed bird, as if it were a male rival. Eventually, a male pairs up with a female and begins following her closely until she signals that she’s ready to mate, by fluttering her wings and giving a fast series of chips. This display also attracts other males, which may mate with the female behind her mate’s back. The females themselves may defend their territories against other females. Once the nestlings hatch and the parents are busy feeding the young brood, they relax their territorial defense. Nest predators include snakes, mice, chipmunks, raccoons, skunks, and possums, while adult yellowthroats are sometimes prey for Loggerhead Shrikes, Northern Harriers, Merlins, and American Kestrels. On wintering grounds, Common Yellowthroats may forage in mixed-species flocks but are usually solitary.Back to top

Conservation

Conservation Low ConcernCommon Yellowthroats are numerous but they declining by almost 1% per year between 1966 and 2014, resulting in a cumulative decline of about 38%, according to the North American Breeding Bird Survey. Partners in Flight estimates the global breeding population at 87 million with 54% spending some part of the year in the U.S., 58% in Mexico, and 41% breeding in Canada. They rate a 9 out of 20 on the Continental Concern Score and are not on the 2014 State of the Birds Watch List. Two sedentary populations have declined sharply from habitat degradation: one subspecies in the San Francisco Bay region dropped 80-95 percent in the past century; another, in Brownsville, Texas, fell so far that it was thought extinct. Both populations remain at risk, largely from wetland degradation and conversion to agricultural and urban landscapes. Rangewide, yellowthroats probably suffer most from habitat degradation and loss. Because they are insectivores and often live in wetlands, they are also susceptible to poor water quality and to pesticides and other pollutants. Common Yellowthroats are not the focus of any management efforts, but they probably benefit indirectly from efforts used for other species, such as waterfowl.Back to top

Backyard Tips

Your yard could attract Common Yellowthroats if it is fairly large (yellowthroat territories are sometimes as small as 0.5 acre) and features dense or tangled, low-growing grasses and other vegetation.

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Credits

Guzy, Michael J. and Gary Ritchison. 1999. Common Yellowthroat (Geothlypis trichas), 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. 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., J. E. Hines, J. E. Fallon, K. L. Pardieck, Jr. Ziolkowski, D. J. and W. A. Link. The North American Breeding Bird Survey, results and analysis 1966-2013 (Version 1.30.15). USGS Patuxtent Wildlife Research Center 2014b. Available from http://www.mbr-pwrc.usgs.gov/bbs/.

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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