About Salpinctes obsoletus (Say, 1822)
The rock wren, scientifically named Salpinctes obsoletus (Say, 1822), measures 12.5–15 cm (4.9–5.9 in) in total length, with a wingspan of 22–24 cm (8.7–9.4 in). There are consistent sex-based differences in most of its measurements: males have an average bill length of 18.7 mm (0.74 in), while females have an average bill length of 17.8 mm (0.70 in). Average wing length is 70.3 mm (2.77 in) for males and 67.8 mm (2.67 in) for females. Average tail length is 51.9 mm (2.04 in) for males and 47.8 mm (1.88 in) for females. Unlike other measurements, average body mass shows males are slightly smaller at 15.7 g (0.55 oz), while females average 17.2 g (0.61 oz). In terms of plumage, rock wrens have grey-brown upperparts marked with small black and white spots, pale grey underparts, and a light brown rump. Key identifying features include a light grey line running through the eye, a long sharp bill, a speckled light grey throat, a long barred tail, zebra-patterned undertail coverts, and dark legs. Juvenile plumage closely resembles adult plumage, differing only by having slightly more vibrant buff coloration similar to washed-out cinnamon, fluffier body feathers, and no dark streak or spots on the underparts. Rock wrens can sometimes be confused with canyon wrens, which share superficially similar coloration and overlapping habitat. However, canyon wrens can be distinguished by their solid white throats and generally brighter, less muddled plumage. For distribution and habitat: Rock wrens are permanent residents across the southern portion of their range, which includes California, western Washington, northern Nevada, northern Arizona, northern New Mexico, southern Guatemala, southern Nicaragua, northwestern Costa Rica, Panama, inland Mexico (including Baja California), Guadalupe Island, and San Benito Island. They are occasional vagrants in the eastern United States. During the breeding season, their range extends north to the southern interior of British Columbia, as well as Wyoming, Montana, Idaho, and Utah. They are most commonly found in open rocky habitats, including exposed rock outcrops, canyons, and cliffs. Rock is not a strict requirement, however, as they can also live in large eroded sandbanks. They are rare in urban areas, and prefer rocky areas that have at least some steep slopes, enough shrubbery for foraging, and plenty of crevices for nesting. Rock wrens tolerate a very wide range of altitudes, breeding from 60 m (200 ft) to 3,600 m (11,800 ft) above sea level, and are most frequently found at altitudes below 2,000 m (6,600 ft).
