Junco hyemalis

Dark-eyed Junco is a complex taxon of identifiable forms, groups and subspecies. In mainland North America, 4 of these were formerly classified as separate species, the Slate-colored, White-winged, Oregon and Gray-headed juncos. All four of these subspecies winter in Texas along with two other forms, the Pink-sided and Red-backed juncos (Oberholser 1974, Am, Ornithol. Union 1998).

DISTRIBUTION. During the 1987-1992 field work of the TBBA project, observers reported 9 breeding records for Dark-eyed Juncos. Of these, 3 were confirmed in latilong-quad 31104-H7 in the Guadalupe Mountains where Oberholser (1974) reported breeding by the Red-backed Junco form (J. h. dorsalis). The Guadalupes are the only site where this author reported breeding in Texas by Dark-eyed Junco. Two probable records also came from this same latilong-quad and another from 31104-H8. The final probable record and 2 possible records deserve further study. The most interesting of these is a possible in 30104-F2 in the Davis Mountains where breeding has not been reported.

Elsewhere Dark-eyed Juncos breed from Alaska across Canada to Southern Labrador and northern Newfoundland and south into the northeastern United States and the Appalachian Mountains (Slate-colored Junco). The remaining forms breed from southwestern Canada south through the western United States to southern California, Arizona and New Mexico. In winter northern populations move south to the entire United States (except the Florida peninsula) and northern Mexico (Howell and Webb 1995, Nolan et al. 2002, Sauer et al. 2005).

SEASONAL OCCURRENCE. This taxon winters in Texas from as early as September 2 until May 27 with the largest numbers present from mid-October to mid-April.. The most common form in winter is Slate-colored Junco found mostly through the eastern two-thirds of the state. Oregon and Gray-headed juncos are usually found in the western half of the state. The breeding season of the Red-backed Junco in the Guadalupe Mountains extends from mid-April to mid-August (young birds in a nest as late as August 5).. This race is resident in the Trans-Pecos region (Oberholser 1974, Lockwood and Freeman 2004).

BREEDING HABITAT. Red-backed Juncos breed in the Guadalupe Mountains from 2100 to 2650 m (7000 to 8700 ft) in pine-Douglas fir forests (Oberholser 1974). In Arizona 87% of breeding records for this form came from habitats containing ponderosa pine mixed with other species such as pinyon pine, oak or Douglas fir (LaRue 2005).

The female selects a nest site almost always on the ground, a natural cavity in the soil or among rocks, often hidden from view by overhanging vegetation or rocks. The cavity is lined by the female with coarse grasses and dead leaves to form a cup with an inner layer of fine grasses, hair and sometimes feathers. The outside diameter is 8.9 cm (3.5 in), inside diameter is 5.7 cm (2.3 in) and cup depth 4.3 cm (1.7 in; Nolan et al. 2002).

The female lays 3-5, slightly glossy, pale bluish-white to white eggs (see Harrison [1979] for a photo of markings). The incubation period is 12-13 days and nestlings fledge 9-12 days after hatching and feed themselves 2 weeks after leaving the nest. Two successful clutches may be raised in one season. Rates of parasitism by Brown-headed Cowbirds (Molothrus ater) vary widely (Harrison 1979, Nolan et al. 2002).

STATUS. Dark-eyed Junco is an uncommon to abundant migrant and winter resident across the northern two-thirds of Texas. The Red-backed form is a common breeder (within its lmited habitat) at the upper elevations in the Guadalupe Mountains and an uncommon and local winter resident elsewhere in the Trans-Pecos region (Lockwood and Freeman 2004). The Breeding Bird Survey does not sample juncos in Texas, but across the United States and Canada data from 1168 routes produced a statistically significant population trend of -1.5% population change per year for 1966-2005 and -2.0% from 1090 routes for 1980-2005 (Sauer et al. 2005). These relatively modest trends are an encouraging sign for the future of Dark-eyed Juncos in Texas.  Text by Robert C. Tweit (2006)

Literature cited.