Voice: Song: Musical long dry trill Call: Chip note in series
Dark-eyed juncos are thought of as the “snowbirds” of the temperate zone. Over most of the eastern United States as winter arrives, juncos appear in a variety of habitats including open woodlands, fields, roadsides, parks and are more often seen on the ground foraging under bird feeders. By April most dark-eyed juncos retreat north to breeding grounds. Sixty-six percent of the global population of Dark-eyed Junco breeds in the boreal forest of North America. However some populations including those of The Holden Arboretum’s can remain all year round.
During winter dark-eyed juncos forage in large mix species flocks with birds such as sparrows and bluebirds. They forage on the ground, hoping, rather than walking, pecking or scratching at the leaf litter to find food. They often have a pecking order in which earlier arrivals tend to rank higher than late arrivals. Primarily seed-eaters, seeds of chickweed (Stellaria), buckwheat (Fagopyrum), lamb’s quarters (Chenopodium), and sorrel (Rumex) make up about 75% of their year-round diet During the breeding season, dark-eyed juncos also eat insects including beetles, moths, butterflies, caterpillars, ants, wasps, and flies.
Dark-eyed juncos breed in mature forests across most of North America at elevations ranging from sea level to more than 11,000 feet. They can be found breeding in coniferous forests including pine (pinus), fir (abies), spruce (picea), as well as in deciduous forests such as aspen (populus), cottonwood (aigeiros) , oak (quercus), maple (acer), and hickory. They prefer high quality mature forest canopy, with good leaf litter, healthy herbaceous layer, decaying trees, and running water. They tend to choose breeding areas where sharon conglomerate rock outcrops, canada hemlock (tsuga canadensis) and yellow birch (betula alleghaniensis) are present.
Female dark-eyed juncos choose a ground nesting site, frequently on a sloping bank concealed under a protruding rock, among roots, under a log, or at the base of plant stems. On occasion nests can be built in shrubs, conifer branches, or tree cavities no higher than 8 feet above ground. Depending on the nesting habitat, dark-eyed juncos females construct their nests out of various materials. Nests may be constructed with a fine lining of grasses or pine needles or have a support of twigs, leaves and moss lined with grasses, ferns, rootlets, hair, and moss. It’s rare for a junco to reuse a nest.
Females usually have 1-2 broods, sets of offspring, per year. They lay 3-5 whitish to bluish white or pale gray eggs, with markings of brown and gray often concentrated at larger end. Females incubate eggs for 11-13 days. Both parents feed the nestlings. Nestlings open their eyes after five days. Feathers are present in seven days. Young leave the nest 9-13 days after hatching, and are usually dependent on there parents for 3 more weeks.
A recent estimate indicates dark-eyed junco populations are stable. However North American Breeding Bird Survey reports that populations have declined by about 1.2 percent per year between 1966 and 2010, resulting in a cumulative decline of 41 percent. Declines could be due to habitat destruction. Partners in Flight estimate the global breeding population at 200 million with 81 percent spending some part of the year in the U.S., 65 percent in Canada, and 7 percent in Mexico.