Rufous-crowned Sparrow

The rufous-crowned sparrow is a smallish sparrow at 5.25 inches (13.3 cm) in length, with males tending to be larger than females. It ranges from 15 to 23 g (0.53 to 0.81 oz) in weight and averages about 19 g (0.67 oz). It has a brown back with darker streaks and gray underparts. Its wings are short, rounded, and brown and lack wingbars, or a line of feathers of a contrasting color in the middle of the bird's wing. The sparrow's tail is long, brown, and rounded. The face and supercilium (the area above the eye) are gray with a brown or rufous streak extending from each eye and a thick black streak on each cheek. The crown ranges from rufous to chestnut, a feature which gives it its common name, and some subspecies have a gray streak running through the center of the crown. The bill is yellow and cone-shaped. The sparrow's throat is white with a dark stripe. Its legs and feet are pink-gray. Both sexes are similar in appearance, but the juvenile rufous-crowned sparrow has a brown crown and numerous streaks on its breast and flanks during the spring and autumn. The song is a short, fast, bubbling series of chip notes that can accelerate near the end, and the calls include a nasal chur and a thin tsi. When threatened or separated from its mate, the sparrow makes a dear-dear-dear call.

This bird is found in the southwestern United States and Mexico from sea level up to 9,800 feet (3,000 m), though it tends to be found between 3,000 and 6,000 feet (910 and 1,830 m). It lives in California, southern Arizona, southern New Mexico, Texas, and central Oklahoma south along Baja California and in western Mexico to southern Puebla and Oaxaca. In the midwestern United States, the sparrow is found as far east as a small part of western Arkansas, and also in a small region of northeastern Kansas, its most northeastern habitat. The range of this species is discontinuous and is made up of many small, isolated populations. The rufous-crowned sparrow is a non-migratory species, though the mountain subspecies are known to descend to lower elevations during severe winters. Male sparrows maintain and defend their territories throughout the year. This sparrow is found in open oak woodlands and dry uplands with grassy vegetation and bushes. It is often found near rocky outcroppings. The species is also known from coastal scrublands and chaparral areas. The rufous-crowned sparrow thrives in open areas cleared by burning.

The average territory size of rufous-crowned sparrows in the chaparral of California ranges from 2 acres (0.81 ha) to 4 acres (1.6 ha). The density of territories varies by habitat, including 2.5 to 5.8 territories per 99 acres (40 ha) of three- to five-year-old burned chaparral to 3.9 to 6.9 territories for the same amount of coastal scrubland. One pair tends to be supported by a territory, although birds without a mate have been seen sharing a territory with a mated pair. This sparrow is awkward in flight and primarily uses running and hopping to move. The rufous-crowned sparrow will at times forage in pairs during the breeding season, and in family-sized flocks in late summer and early autumn. During the winter they can occasionally be found in loose mixed-species foraging flocks. Predators of adult sparrows include house cats and small raptors like Cooper's and sharp-shinned hawks, American kestrels, and white-tailed kites. The nests may be raided by a range of species including mammals and reptiles such as snakes, though nest predation has not yet been directly observed, and nesting sparrows have been observed using three kinds of displays to distract potential predators; the rodent run, the broken wing, and the tumbling off the bush. Birds adopt a rodent run display to distract predators. …