Rufous-crowned Sparrow

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Common Name: Rufous-crowned Sparrow
Scientific Name: Aimophila ruficeps

Size: 5.25 inches (13.6 cm)

Habitat: North America; found in the southwestern United States and Mexico from sea level up to 9,800 feet, though it tends to be found between 3,000 and 6,000 feet. 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.

It 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.

Status: Least Concern. Global Population: 2,400,000 mature individuals. In years without sufficient rains, many birds fail to breed and those that do produce fewer offspring. Some of the local populations of this bird are threatened and declining in number. The island subspecies and populations have declined in some cases: A. r. sanctorum of the Todos Santos Islands is believed to be extinct, and the populations on Santa Catalina Island and Baja California's Islas de San Martin have not been observed since the early 1900s. Populations of the species in southern California are also becoming more restricted in range because of urbanization and agricultural development in the region. Additionally, the sparrow is known to have been poisoned by the rodenticide, warfarin, though more research is needed to determine the effects of pesticides on the Rufous-crowned Sparrow.

Diet: This sparrow feeds primarily on small grass and forb seeds, fresh grass stems, and tender plant shoots during autumn and winter. During these seasons, insects such as ants, grasshoppers, ground beetles, and scale insects as well as spiders make up a small part of its diet. In the spring and summer, the bird's diet includes a greater quantity and variety of insects. It forages slowly on or near the ground by walking or hopping under shrubs or dense grasses.

Nesting: Both sexes are similar in appearance although males tend to be larger than females. It has a brown back with darker streaks and gray under parts. 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.

The Rufous-crowned Sparrow breeds in sparsely vegetated scrubland. Males attract a mate by singing from regular positions at the edge of their territories throughout the breeding season. These birds are monogamous, taking only one mate at a time, and pairs often remain together for several years. If singing males come within contact of each other, they may initially raise their crowns and face the ground to display this feature; if that fails to make the other bird leave, they stiffen their body, droop their wings, raise their tails, and stick their head straight out. Males guard their territories year-round.

The female bird builds a bulky, thick-walled open-cup nest typically on the ground, though occasionally in a low bush up to 18 in (46 cm) above it, from dried grasses and rootlets, sometimes with strips of bark, small twigs, and weed stems. Nests are well hidden, as they are built near bushes or tall grasses or overhanging rock with concealing vegetation. Once a sparrow chooses a nesting site, it tends to return to the site for many years. It lays between two and five eggs at a time and typically only raises one brood a year. The eggs are an unmarked, pale bluish-white. Incubation of the eggs lasts 11 to 13 days and is performed solely by the female. The hatchlings are naked and quills do not begin to show until the third day. Only females brood the nestlings, though both parents may bring whole insects to their young. When a young Rufous-crowned Sparrow leaves the nest after eight or nine days, it is still incapable of flight, though it can run through the underbrush; during this time it is still fed by the parents. Juveniles tend to leave their parent's territory and move into adjacent habitat in autumn or early winter. Reproductive success varies strongly with annual rainfall and is highest in wet El Niño years, since cool rainy weather reduces the activity of snakes, the main predator of the sparrow's nests.

Cool Facts: The average territory size of Rufous-crowned Sparrows in the chaparral of California ranges from 2 acres.

There are 12 recognized subspecies:

  • A. r. ruficeps, the nominate subspecies, was described by Cassin in 1852. It is found in the coastal ranges of California and on the western slopes of the Sierra Nevada. This subspecies is darker and noticeably smaller than A. r. eremoeca and has distinct rufous-brown streaking on its upper parts.
  • A. r. canescens was described by American ornithologist W.E. Clyde Todd in 1922, and it is found in southwestern California and northeast Baja California as far east as the base of the San Pedro Martir. While the species itself is listed as of Least Concern, this subspecies is listed as a "species of special concern" by the California Department of Fish and Game, signifying that this population is threatened with extinction. It appears to be extremely similar to A. r. ruficeps but is darker.
  • A. r. obscura, described by Donald R. Dickey and Adriaan van Rossem in 1923, is found in the Channel Islands of California on Santa Cruz, Anacapa, and formerly on Santa Catalina. While the Santa Catalina population has not been observed since 1863, the subspecies seems to have colonized Anacapa Island. No records exist of them before 1940. This subspecies is similar to A. r. canescens but is darker.
  • A. r. sanctorum was described by van Rossem in 1947. It was found on the Todos Santos Islands off the coast of northwest Baja California. This subspecies is believed to be extinct. This is the darkest of the coastal subspecies, especially on its underbelly.
  • A. r. sororia was described by Robert Ridgway in 1898, and it is found in the mountains of southern Baja California, specifically the Sierra de la Laguna. It is the palest of the coastal subspecies.
  • A. r. scottii, described by George Sennett in 1888, is found from northern Arizona to New Mexico south to northeastern Sonora and northwestern Coahuila. It appears to be a darker gray than A. r. eremoeca and has narrower and darker rufous streaks on its breast.
  • A. r. rupicola was described by van Rossem in 1946.[12] It is found in the mountains of southwestern Arizona. It is similar in appearance to A. r. scottii but is darker and grayer on its back.
  • A. r. simulans was described by van Rossem in 1934, and it is found in northwestern Mexico from southeastern Sonora and southwestern Chihuahua to Nayarit and northern Jalisco. It has more rufous coloration on its back and is paler on its underbelly than A. r. scottii.
  • A. r. eremoeca was described by N. C. Brown in 1882. It is found from southeastern Colorado to New Mexico, Texas, northern Chihuahua, and central Coahuila. It has grayish upper parts and a dark breast.
  • A. r. fusca, described by Edward William Nelson in 1897, is found in western Mexico from southern Nayarit to southwestern Jalisco, northern Colima, and Michoacan. It is darker and more rufous on its upper parts than A. r. australis. It also possesses a darker rufous crown which does not show a gray stripe down the middle.
  • A. r. boucardi was described by Philip Sclater in 1867, and it is found in eastern Mexico from southern Coahuila to San Luis Potosí, northern Puebla, and southern Oaxaca. This subspecies is darker than A. r. eremoeca and has dull brown, not rufous, streaking on the chest.
  • A. r. australis, described by Edward William Nelson in 1897, occurs in southern Mexico from Guerrero to southern Puebla and Oaxaca. A. r. scottii is similar in appearance, but this subspecies is smaller and has a shorter bill.

Found in Songbird Remix Sparrows of the World

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