Dark-eyed Junco - Ecology

Ecology

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 the winter range and breed there. 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.

These birds forage on the ground. In winter, they often forage in flocks that may contain several subspecies. They mainly eat insects and seeds.

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 and are lined with fine grasses and hair. Normally two clutches of 4 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.