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Dark-eyed junco

The dark-eyed junco (Junco hyemalis) is a species of the juncos, a genus of small grayish American sparrows. This bird is common across much of temperate North America and in summer ranges far into the Arctic. It is a very variable species, much like the related fox sparrow (Passerella iliaca), and its systematics are still not completely untangled.
The white-winged junco has a medium-gray head, breast, and upperparts with white wing bars. Females are washed brownish. It has more white in the tail than the other forms. It is a common endemic breeder in the Black Hills area of South Dakota, Wyoming, Nebraska, and Montana, and winters south to northeastern New Mexico.
Often considered part of the Oregon group, it has a lighter gray head and breast than the Oregon group with contrasting dark lores. The back and wings are brown. It has pinkish-cinnamon color that is richer and covers more of the flanks and breast than in Oregon juncos. It breeds in the northern Rocky Mountains from southern Alberta to eastern Idaho and western Wyoming; it winters in central Idaho and nearby Montana and from southwestern South Dakota, southern Wyoming, and northern Utah to northern Sonora and Chihuahua.
The extremely rare Guadalupe junco is also considered part of this species by some authors, namely the IUCN, which restores it to subspecies status in 2008. Other authors consider it a species in its own right – perhaps a rather young one, but certainly this population has evolved more rapidly than the mainland juncos due to its small population size and the founder effect.
Their breeding habitat is coniferous or mixed forest areas throughout North America. In otherwise optimal conditions they also utilize other habitat, but at the southern margin of its range it can only persist in its favorite habitat. Northern birds migrate further south, arriving in their winter quarters between mid-September and November and leaving to breed from mid-March onwards, with almost all gone by the end of April or so. Many populations are permanent residents or altitudinal migrants, while in cold years birds may choose to stay in their winter range and breed there. For example, in the Sierra Nevada of eastern California, J. hymealis populations will migrate to winter ranges 5,000–7,000 feet (1,500–2,100 m) lower than their summer range. In winter, juncos are familiar in and around towns, and in many places are the most common birds at feeders. The slate-colored junco is a rare vagrant to western Europe and may successfully winter in Great Britain, usually in domestic gardens.
They usually nest in a cup-shaped depression on the ground, well hidden by vegetation or other material, although nests are sometimes found in the lower branches of a shrub or tree. The nests have an outer diameter of about 10 cm (3.9 in) and are lined with fine grasses and hair. Normally two clutches of four eggs are laid during the breeding season. The slightly glossy eggs are grayish or pale bluish-white and heavily spotted (sometimes splotched) with various shades of brown, purple or gray. The spotting is concentrated at the large end of the egg. The eggs are incubated by the female for 12 to 13 days. Young leave nest between 11 and 14 days after hatching.