UKBirds

Dark-Eyed Junco

Junco hyemalis

The Dark-eyed Junco (Junco hyemalis) is the best-known 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 is still not completely untangled.

Adults generally have gray heads, necks, and breasts, gray or brown backs and wings, and a white belly, but show a confusing amount of variation in plumage details. The white outer tail feathers flash distinctively in flight and while hopping on the ground. The bill is usually pale pinkish.

Males tend to have darker, more conspicuous markings than the females. Also they are 5-6.5 in (13-17 cm) in length. Juveniles often have pale streaks and may even be mistaken for Vesper Sparrows (Pooecetes gramineus) until they acquire adult plumage at 2 to 3 months. But junco fledglings' heads are generally quite uniform in color already, and initially their bills still have conspicuous yellowish edges to the gape, remains of the fleshy wattles that guide the parents when they feed the nestlings.

The song is a trill similar to the Chipping Sparrow's (Spizella passerina), except that the Red-backed Junco's (see below) song is more complex, similar to that of the Yellow-eyed Junco (Junco phaeonotus). Calls include tick sounds and very high-pitched tinkling chips.

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.