
Audubon Scientists Reveal Migration Bottlenecks Used by Tens of Millions of Birds
New study details how California’s Central Valley and the Colorado River Delta in Mexico provide food and shelter for globally significant numbers of migratory birds.
Adult male. Photo: Amado Demesa/Flickr (CC BY SA 2.0)
Setophaga nigrescens
Conservation status | Common and widespread in the west. |
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Family | Wood Warblers |
Habitat | Dry oak slopes, pinyons, junipers, open mixed woods. Breeds in dry coniferous and mixed woods, especially of oak, juniper, and pinyon pine. Also frequents manzanita thickets and chaparral. Prefers open areas, as in second-growth, forest edges, or dry hillsides or canyons. In winter in Mexico, found in lowland dry forest, dense thorn scrub, and pine-oak woods. |
The most common method of foraging during the breeding season is by searching for insects among leaves of low growing foliage; also hovers briefly to pick insects from various surfaces. Also flies out after flying insects. In migration and winter, often forages in mixed flocks with other species.
Usually 4, sometimes 3-5. Creamy white, with brown marks often concentrated at larger end. Incubated by female for unknown number of days. Young: Both parents feed the nestlings. Age at which young leave the nest is not well known. Normally only 1 brood per year.
Both parents feed the nestlings. Age at which young leave the nest is not well known. Normally only 1 brood per year.
Mostly insects. Diet is not known in detail. Known to feed especially on oakworms and other green caterpillars.
Details of nesting behavior not well known. Males arrive on breeding grounds in March or April in southern part of the range, in late May in the north. Nest site varies; may be 4-10' from trunk on horizontal branch in larger tree such as fir or oak, or closer to the main trunk in a smaller tree or shrub. Usually placed 7-35' above the ground, but can be 1-50' up. Nest is a neat, open cup, built probably by both sexes, made of weeds, dry grass, and plant fiber; lined with feathers, fur, hair, and moss.
Audubon’s scientists have used 140 million bird observations and sophisticated climate models to project how climate change will affect this bird’s range in the future.
Zoom in to see how this species’s current range will shift, expand, and contract under increased global temperatures.
Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.
New study details how California’s Central Valley and the Colorado River Delta in Mexico provide food and shelter for globally significant numbers of migratory birds.
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