Dark-eyed Junco

The Dark-eyed Junco, one of the most common and familiar North American passerines. It is familiar because of its ubiquity, abundance, tameness and conspicuous ground-foraging winter flocks, which are often found in suburbs (especially at feeders), at edges of parks and similar landscaped areas, around farms and along rural roadsides and stream edges. It occurs across the continent from northern Alaska south to northern Mexico.

Adult Male (spring/summer)

Adult Male (spring/summer)
Oregon Juncos have a very dark gray to black hood, with a convex bib on their breast, white belly and undertail coverts, rusty brown flanks, dark chestnut back and scapulars. Wings are brownish gray. Tail is gray with conspicuous white outer tail feathers that flash when the bird takes flight. Beak flesh coloured and eyes black.

Adult Female (spring/summer)

Duller overall, with gray hood, often brown on the nape and dull brown back. Flanks pale peach.

Juvenile

Forehead and crown brown, profusely streaked with dark brown; back, rump, and uppertail-coverts rusty, streaked with darker brown; tail dark brown with white outer tail feathers; wings blackish, with coverts tipped with whitish or buffy white, forming two whitish wing-bars; throat and breast heavily streaked; flanks strongly tinged with buff; belly white or buffy white.

General:

Medium sized sparrow, which exhibits marked geographic variation in plumage colouration and moderate variation in size. Length: 14-16cm. Wing: 18-25cm. 18-30grams.

Behaviour:

This lively territorial bird is a ground dweller and feeds on seeds and small fruits in the open. It also moves through the lower branches of trees and seeks shelter in tangles of shrubs. Males sing persistently from an exposed perch.

Habitat:

Openings and edges of conifers and mixed woods; in winter roadsides, parks, suburban gardens, or patchy wooded areas in small flocks. Generally breeds in open coniferous forests.

Information:

Audubon stated that “there is not an individual in the Union who does not know the little Snow-Bird”, and to some people “snowbird” is the junco’s name today.
Until the 1970s the currently recognized Dark-eyed Junco was split into 5 distinct species, 3 of them comprising 2 or more subspecies. The American Ornithologist Union (1973, 1982) lumped these 5 species but acknowledged the distinctiveness of the former species by designating them and their subspecies as “informal” groups of Junco hyemalis. Each group bears the scientific and vernacular name that it previously bore as a species: hyemalis (Slate Coloured Junco); aikeni (White-wing Junco); oreganus (Oregon Junco); caniceps (Grey-headed Junco); and insularis (Guadalupe Junco). There are 3-5, usually 4, white, sometimes tinged with green, and spotted or blotched with reddish brown eggs. They are found in a compact nest of rootlets, shreds of bark, twigs, and mosses, lined with grasses and hair, on the ground protected by a rock ledge, mud bank, tufts of weeds, or a fallen log.

Similar species:

Conservation Status:

Listed as Least Concern.

Capture Rates

Colony Farm is a preferred winter habitat for Oregon Junco. This is reflected in high capture rates during winter banding sessions in October through March. As the species moves to their breeding territory in forested areas at higher elevation, numbers at the banding station decrease.

Molt Summary:

PF: HY partial, PB: AHY complete, PA limited
Preformative molt includes most to all med covs, 3 – 10 inner gr covs, sometimes 1 – 2 (rarely 3) terts, and occasionally 1 – 2 central rects (r1)
Northern sub species replace fewer gr covs and only occasionally replace 1 – 2 terts (often just s9)
Males also may replace more feathers than females – more study needed
Up to 3 pp covs and 3 middle ss (among s4 – s6) rarely can be retained in the adult PB; this likely occurs more often during the 2nd PB than during subsequent adult PBs – more study needed
The PAs are limited to body feathers (primarily around the head), and include no wing covs or flight feathers.

Sexing:

Male: head and lores black, back and flanks medium dark pinkish brown.

Female: head and lores medium gray, back dark brown; flanks bright pale brownish pink.

Wing chord: Somewhat helpful in sexing – always age birds first prior to sexing!

Juvenile has plumage with distinct streaking and white outer tail feathers. Juv M=F

Other characteristics such as prominent gape, dull eye colour and loosely textured undertail coverts are reliable for ageing birds in juvenal plumage.