Yellow-rumped Warbler

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Common Name: Yellow-rumped Warbler
Scientific Name: Dendroica coronata

Size: 4.7–5.5 inches (12-14 cm); Wingspan: 7.5-9.1 inches (19-23 cm)

Habitat: North America; breeds from eastern North America west to the Pacific, and southward from there into Western Mexico. The Myrtle race has a northerly and easterly distribution, with the Audubon's race further west.

In summer, they frequent open coniferous forests and edges, and to a lesser extent deciduous forests (such as in patches of aspen, birch, or willow). In fall and winter, they move to open areas with fruiting shrubs or scattered trees, such as parks, streamside woodlands, open pine and pine-oak forest, dunes (where bayberries are common), and residential areas. On their tropical wintering grounds they live in mangroves, thorn scrub, pine-oak-fir forests, and shade coffee plantations.

Status: Not Threatened. Global population: Unknown population. Yellow-rumped Warblers are common and widespread. Their populations are stable or increasing in most areas. Migrating Yellow-rumped Warblers, like many migrants, are frequently killed in collisions with radio towers, buildings, and other obstructions.

Diet: Insects and occasional berries. They eat mainly insects in the summer, including caterpillars and other larvae, leaf beetles, bark beetles, weevils, ants, scale insects, aphids, grasshoppers, caddisflies, craneflies, and gnats, as well as spiders. They also eat spruce budworm, a serious forest pest, during outbreaks. On migration and in winter they eat great numbers of fruits, particularly bayberry and wax myrtle, which their digestive systems are uniquely suited among warblers to digest. This is one reason why Yellow-rumped Warblers winter so much farther north than other warbler species. Other commonly eaten fruits include juniper berries, poison ivy, poison oak, greenbrier, grapes, Virginia creeper, and dogwood. They will eat wild seeds such as from beach grasses and goldenrod, and they may come to feeders, where they'll take sunflower seeds, raisins, peanut butter, and suet. On their wintering grounds in Mexico, they've been seen sipping the sweet honeydew liquid excreted by aphids.

Yellow-rumped Warblers typically forage in the outer tree canopies at middle heights. Male Yellow-rumped Warblers tend to forage higher in trees than females do. They are very active, flycatching insects in midair and sometimes on long flights. They cling to the bark surface to look for hidden insects more than many warblers do, but they also frequently sit on exposed branches and catch passing insects like a flycatcher does. In winter they eat berries from shrubs, and they often travel in large flocks. If another bird gets too close, Yellow-rumped Warblers indicate the infraction by holding the body horizontally, fanning the tail, and raising it to form a right angle with its body.

Nesting: Yellow-rumped Warblers are fairly large, full-bodied warblers with a large head, sturdy bill, and long, narrow tail. In summer, both sexes are a dark gray with flashes of white in the wings and yellow (or white) on the face, sides, and rump. Males are dramatically shaded whereas females are duller and may show some brown. Winter birds are paler brown, with bright yellow rump and usually some yellow on the sides. Between the two races, Audubon and Myrtle, Audubon males have yellow throats whereas as Myrtle males have white throats. Myrtle males and females also have a defining white “eyebrow” marking.

When males court females, they fluff their feathers, raise their wings and the feathers of the crown, and hop from perch to perch, chipping. They may also make display flights in which they glide back and forth or fly slowly with exaggerated wingbeats.

Females build the nest, sometimes using material the male carries to her. The nest is a cup of twigs, pine needles, grasses, and rootlets. She may also use moose, horse, and deer hair, moss, and lichens. She lines this cup with fine hair and feathers, sometimes woven into the nest in such a way that they curl up and over the eggs. The nest takes approximately 10 days to build and is 3-4 inches across and 2 inches tall. The eggs are colored white with speckles of brown, reddish-brown, gray, or purplish gray on them. 1 to 7 eggs are laid and the incubation time is 12 to 13 days.

Cool Facts: There are two forms of Yellow-rumped Warbler found in the United States, Audubon’s and Myrtle. They were once considered different species, but in 1973 the American Ornithologists' Union elected to merge them into what we now call the Yellow-rumped Warbler. The Myrtle form (S. c. coronata) was apparently separated from the others by glaciation during the Pleistocene, and the Audubon's form (S. c. auduboni) may have originated more recently through hybridization between the Myrtle Warbler and the Black-fronted or Mexican form (S. c. nigrifrons). There is an additional form, Goldman’s (S. c. goldmani) found in Guatemala. It resembles Audubon's but has a white lower border to the yellow throat and otherwise darker plumage; males replace the slate blue of Audubon's with black.

The Yellow-rumped Warbler is the only warbler able to digest the waxes found in bayberries and wax myrtles. Its ability to use these fruits allows it to winter farther north than other warblers, sometimes as far north as Newfoundland. On the west coast, the Yellow-rumped Warbler is particularly fond of the fruit on laurel sumac.

When Yellow-rumped Warblers find themselves foraging with other warbler species, they typically let Palm, Magnolia and Black-throated Green warblers do as they wish, but they assert themselves over Pine and Blackburnian warblers.

The oldest known Yellow-rumped Warbler of the “Myrtle” race was 8 years 9 months old. The oldest known individual of the “Audubon’s” race was 10 years old.


Found in Songbird Remix Woodland Jewels

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