![]() On their wintering grounds in Mexico they've been seen sipping the sweet honeydew liquid excreted by aphids. They 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. Other commonly eaten fruits include juniper berries, poison ivy, poison oak, greenbrier, grapes, Virginia creeper and dogwood. The ability to use these fruits allows it to winter farther north than other warblers, sometimes as far north as Newfoundland. It is the only warbler able to digest such waxy material. When bugs are scarce, the myrtle warbler also eats fruit, including the wax-myrtle berries which gave it its name. They also eat spruce budworm, a serious forest pest, during outbreaks. Common foods include caterpillars and other larvae, leaf beetles, bark beetles, weevils, ants, scale insects, aphids, grasshoppers, caddisflies, craneflies, and gnats, as well as spiders. Other places yellow-rumped warblers have been spotted foraging include picking at insects on washed-up seaweed at the beach, skimming insects from the surface of rivers and the ocean, picking them out of spiderwebs, and grabbing them off piles of manure. Beyond gleaning from leaves like other New World warblers, they often flit, flycatcher-like, out from their perches in short loops, to catch flying insects. The species is perhaps the most versatile foragers of all warblers. Goldman's warbler, of Guatemala, 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.Īudubon's and the myrtle are among North America's most abundant neotropical migrants. Females of both forms are more dull, with brown streaking front and back, but still have noticeable yellow rumps. Audubon's warbler also sports a yellow throat patch, while the myrtle warbler has a white throat and eye stripe, and a contrasting black cheek patch. In summers, males of both forms have streaked backs of black on slate blue, white wing patches, a streaked breast, and conspicuous yellow patches on the crown, flank, and rump. ![]() Among standard measurements, the wing chord is 6.3 to 8.4 cm, the tail is 5 to 6.6 cm, the bill is 0.8 to 1.1 cm and the tarsus is 1.8 to 2.2 cm. ![]() Body mass can vary from 9.9 to 17.7 g, though averages between 11 and 14 g. In total length, the species can range from 12 to 15 cm long, with a wingspan of 19 to 24 cm. This is a mid-sized New World warbler, though it is one of the largest species in the Setophaga genus which comprises a lion's share of the species in the family. On their tropical wintering grounds they live in mangroves, thorn scrub, pine-oak-fir forests, and shade coffee plantations. During winter, yellow-rumped warblers find open areas with fruiting shrubs or scattered trees, such as parks, streamside woodlands, open pine and pine-oak forest, dunes, and residential areas. In the Pacific Northwest and the Northeastern U.S., they occur all the way down to sea level wherever conifers are present. and in the central Appalachian Mountains, they are found mostly in mountainous areas. Yellow-rumped warblers spend the breeding season in mature coniferous and mixed coniferous-deciduous woodlands In the western U.S. Among warblers Audubon's is by far the most widespread in North America in winter, and in the northern and central parts of the continent, it is among the last to leave in the fall and among the first to return and is an occasional vagrant to the British Isles and Iceland. The myrtle and Audubon's forms are migratory, traveling to the southern U.S., Mexico, Central America, and the Caribbean for winters. "Goldman's" yellow-rumped warbler is a non-migratory endemic within the highlands of Guatemala and the black-fronted warbler is also a non-migratory Mexican endemic. The yellow-rumped warbler breeds from eastern North America west to the Pacific, and southward from there into Western Mexico. As a male myrtle warbler, this individual has a black "mask". Summer adult male yellow-rumped warblers have slate-blue backs and yellow crowns. The myrtle form was apparently separated from the others by glaciation during the Pleistocene, and the Audubon's form may have originated more recently through hybridization between the myrtle warbler and the Mexican nigrifrons form. ![]() There is a pending proposal to recognize the yellow-rumped warbler as four rather than as the present. Since 1973, the American Ornithologists Union has elected to merge these passerine birds as one species. The yellow-rumped warbler (Setophaga coronata) is a North American bird species combining four closely related forms: the eastern myrtle warbler its western counterpart, Audubon's warbler the northwest Mexican black-fronted warbler and the Guatemalan Goldman's warbler. ![]()
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