Dark-Eyed Junco

Quick Take

• The Dark-Eyed Junco's scientific name quietly encodes a seasonal secret that perfectly describes its relationship with North America.
• Most people assume these birds all look the same, yet six distinct color variants tell a very different story. See the six variants →
• Female juncos use a surprisingly personal technique to build their nests, and no ruler is required. Explore the nesting technique →
• Hundreds of millions of them live across North America, yet there's a quiet trend in their population that conservation data has been tracking since 1966. Check the population trend →

The Dark-Eyed Junco is a species of New World sparrow most notable for its bright white outer tail feathers that can be seen from below during flight. Each year, all of North America experiences a “winter rush” of Dark-Eyed Juncos migrating south from their spring- and summertime perches in the western mountains and Canada.

This bird’s scientific name, Junco hyemalis, alludes to this seasonal sparrow onslaught. Junco comes from the Spanish word for “rush,” from the Latin juncus. Hyemalis is the Latin word for “of the winter.” Hence, winter rush. It should be noted, however, that in Spanish “junco” refers specifically to a reed or rush plant.

Their home for most of the year is coniferous and deciduous forests, where it hops (rather than walks) about on the ground foraging for food and nesting materials. During its winter migration, the Dark-Eyed Junco — the avian “snowbird” — makes use of open woodlands, fields, roadsides, parks, and gardens. They are literally found everywhere, and with hundreds of millions of them calling North America home, it’s no wonder.

Appearance and Subspecies

Approximately 15 subspecies of juncos are recognized, distinguished from one another primarily by their coloring and geographic region, as they are all about the same shape and size. Typically, juncos have gray heads, necks, and breasts; their wings and backs are gray or brown; their bellies are white; and the outer tail feathers are noticeably white in flight. The coloring around their eyes is quite dark, hence the name: Dark-Eyed Junco.

Dark-Eyed Juncos are medium in size, measuring generally 5.5 to 6.3 inches in length with a wingspan between 7.1 and 9.8 inches. These birds weigh barely an ounce, with a typical range of 0.6 to 1.1 ounces.

The subspecies are grouped into six color categories:

• Slate-colored group – These juncos have slate-gray heads, breasts, and upper bodies.

• White-winged group – The subspecies in this group has a medium-gray head, breast, and upper body and features a whiter tail than the other juncos.

• Oregon or brown-backed group – These sparrows have blackish-gray heads and breasts with brown backs and wings.

• Pink-sided group – This subspecies has a lighter gray head and breast than the Oregon subspecies. Its back and wings are brown. A pinkish color covers more of the flanks and breast than the Oregon subspecies.

• Gray-headed group – This bird is mostly light gray with a rusty-brown back.

• Red-backed group – This junco is similar to the gray-headed subspecies, but its bill is more silver in color and features a dark-colored upper and light-colored lower mandible.

Behavior

The breeding season for these birds occurs in northern Canada and at higher elevations in the United States during the late spring and early summer months. These areas are quite remote, so human impact is minimal.

Typically, females build nests near the ground around sloping rocky areas in the tangled roots of fallen trees, although they also build around humans in or underneath buildings, and occasionally, they build just above the ground in branches or building overhangs. 

Their nests, therefore, vary considerably. Location often determines what Juncos use to build their nests. Sometimes, they can just be a lining of vegetation on the ground. If built off the ground, nests resemble what typically comes to mind: a ring of twigs, moss, and leaves. Finer materials such as grass and hair line the inside of the ring. 

A female Junco uses her body to determine the nest’s size, but typically the nest will be between 3 and 5.5 inches across with an inner diameter of about 2.4 to 2.8 inches. It usually takes 3 to 7 days to build a nest. 

Female Dark-Eyed Juncos typically lay between 3 and 5 eggs, although laying 6 does happen. After 12 to 13 days, the eggs hatch. Both Junco parents feed their young. About 9 to 13 days after hatching, the young Juncos leave the nest.

These birds mainly forage on the ground for seeds, primarily from sorrel, lamb’s quarters, chickweed, buckwheat, and other similar grasses. Of course, they do feed at bird feeders and prefer millet over sunflower seeds. During the breeding season, they eat a wider range of foods, including insects such as ants, flies, caterpillars, butterflies, beetles, wasps, and moths.

Dark-Eyed Juncos are very territorial, especially in the summer. They will often attempt to chase off intruders near their nests by diving at them rapidly while chirping excitedly.

The best time to find them is in the winter months throughout the United States and Northern Mexico, where they can often be found foraging on the ground for seeds and insects in partially wooded areas. They tend to travel in mixed-species flocks, which are a delight for bird watchers to observe. 

Threats and Status

Dark-Eyed Juncos typically forage on the ground, so they can make ideal ambush targets for cats, bats, foxes, snakes, eagles, hawks, and owls. But as one of the most common birds in North America, these threats are not significantly affecting their population. It is estimated that several hundred million Dark-Eyed Juncos live on the continent.

However, surveys indicate that the population has been declining by about 0.7% per year since 1966. Generally, though, there is little conservation concern for this bird. Partners in Flight rates the species 8 out of 20 on the Continental Concern Score.