Worthen's sparrow (''Spizella wortheni'') is a species of

American sparrow New World sparrows are a group of mainly New World passerine birds, forming the family Passerellidae. They are seed-eating birds with conical bills, brown or gray in color, and many species have distinctive head patterns. Although they share t ...

that is endemic to northeastern

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

. It was first described by

Robert Ridgway Robert Ridgway (July 2, 1850 – March 25, 1929) was an American ornithologist specializing in systematics. He was appointed in 1880 by Spencer Fullerton Baird, secretary of the Smithsonian Institution, to be the first full-time curator of bird ...

in 1884 and named for the American naturalist Charles K. Worthen. This small bird has been listed as

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...

by the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

since 1994.

Description

''Spizella wortheni'' can range in length from 12.5 to 14 cm. It is identifiable by its distinctive head pattern. It has a grey head with a

rufous Rufous () is a color that may be described as reddish-brown or brownish-red, as of rust or oxidised iron. The first recorded use of ''rufous'' as a color name in English was in 1782. However, the color is also recorded earlier in 1527 as a dia ...

crown, a brown postocular stripe and a pink bill. It has grey-brown upperparts, with dark brown streaks. It has a grey bottom, and dark brown wings and tail. Its wings are "edged paler, with broad whitish to pale buff wing-bar, buffy-rufous tertial and secondary edging, and greyish lesser coverts". Juveniles are characterized by brownish colouration of the head and chest, with dusky streaking on the head and dark brown streaking on the chest and flanks. The song is a dry, chipping trill of 2–3 seconds duration and is described as a cross between that of the

field sparrow The field sparrow (''Spizella pusilla'') is a small New World sparrow in the family Passerellidae. It is about long and weighs about . The head is grey with a rust-coloured crown, white eye-ring and pink bill. The upper parts are brown streake ...

and that of the

chipping sparrow The chipping sparrow (''Spizella passerina'') is a species of New World sparrow, a passerine bird in the family Passerellidae. It is widespread, fairly tame, and common across most of its North American range. There are two subspecies, the east ...

. The species is similar in appearance to the field sparrow (''Spizella pusilla''). However, they differ in plumage, habitat, and song. The species nests from May to July and usually lays three or four eggs. Single-species flocks form after the breeding season and are strongly attracted to permanent sources of water. The species is not migratory; however, a few sightings of individuals have taken place throughout the northwestern region of Mexico. Only one individual has ever been identified (shot) in the United States, and it was by Rieber on June 16, 1884, near

Silver City, New Mexico Silver City is a town in Grant County, New Mexico, United States. It is the county seat and the home of Western New Mexico University. As of the 2010 census the population was 10,315. As of the 2020 census, the population was 9,704. History ...

. This individual, the first of the species to be described, is the

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

Habitat and range

Worthen's sparrow is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to northeastern Mexico and currently occupies a 25 km² range. Populations formerly occurred in

Zacatecas , image_map = Zacatecas in Mexico (location map scheme).svg , map_caption = State of Zacatecas within Mexico , coordinates = , coor_pinpoint = , coordinates_footnotes = , subdivision_type ...

Coahuila Coahuila (), formally Coahuila de Zaragoza (), officially the Free and Sovereign State of Coahuila de Zaragoza ( es, Estado Libre y Soberano de Coahuila de Zaragoza), is one of the 32 states of Mexico. Coahuila borders the Mexican states of N ...

Nuevo León Nuevo León () is a state in the northeast region of Mexico. The state was named after the New Kingdom of León, an administrative territory from the Viceroyalty of New Spain, itself was named after the historic Spanish Kingdom of León. With a ...

, and

Tamaulipas Tamaulipas (), officially the Free and Sovereign State of Tamaulipas ( es, Estado Libre y Soberano de Tamaulipas), is a state in the northeast region of Mexico; one of the 31 states which, along with Mexico City, comprise the 32 Federal Entiti ...

; however, presently it is only known to occur from southeastern

to western

. ''Spizella wortheni'' prefers open, arid shrub-grassland at elevations of . For foraging, the species prefers open areas with low grasses. For nesting and cover, it usually inhabits low, dense shrubs. In 2004, the population was estimated to be 100–120 individuals.

Conservation

The major threat to this species is

habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

. The grassland Worthen's sparrow is specific to has progressively been ploughed for agriculture and grazing. Currently there is a conservation effort being coordinated by the Bird Conservation Alliance and other organizations to protect the Saltillo Savanna in Mexico. The program, known as the Mexican Grasslands Appeal, seeks to purchase over of prime grassland habitat to protect and save this last great North American

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

. By protecting this area, the appeal will conserve habitat for the Worthen's sparrow,

long-billed curlew The long-billed curlew (''Numenius americanus'') is a large North American shorebird of the family Scolopacidae. This species was also called "sicklebird" and the "candlestick bird". The species breeds in central and western North America, migrat ...

burrowing owl The burrowing owl (''Athene cunicularia''), also called the shoco, is a small, long-legged owl found throughout open landscapes of North and South America. Burrowing owls can be found in grasslands, rangelands, agricultural areas, deserts, or an ...

mountain plover The mountain plover (''Charadrius montanus'') is a medium-sized ground bird in the plover family (Charadriidae). It is misnamed, as it lives on level land. Unlike most plovers, it is usually not found near bodies of water or even on wet soil; i ...

Sprague's pipit Sprague's pipit (''Anthus spragueii'') is a small songbird (passerine) in the family Motacillidae that breeds in the short- and mixed-grass prairies of North America. Migratory, it spends the winters in the southwestern United States and norther ...

, and

ferruginous hawk The ferruginous hawk, (''Buteo regalis''), is a large bird of prey and belongs to the broad-winged buteo hawks. An old colloquial name is ferrugineous rough-leg, due to its similarity to the closely related rough-legged hawk (''B. lagopus''). ...

.Bird Conservation Alliance. "Project Saltillo." http://www.birdconservationalliance.org/saltillo/Project_saltillo.cfm

Description

Habitat and range

Conservation

References

Further reading