Rufous-crowned Sparrow
Encyclopedia
The Rufous-crowned Sparrow, Aimophila ruficeps, is a smallish American sparrow
. This passerine
is primarily found across the Southwestern United States
and much of the interior of Mexico, south to the transverse mountain range
, and to the Pacific coast to the southwest of the transverse range. Its distribution is patchy, with populations often being isolated from each other. Twelve subspecies
are generally recognized, though up to eighteen have been suggested. This bird has a brown back with darker streaks and gray underparts. The crown is rufous
, and the face and supercilium
are gray with a brown or rufous streak extending from each eye and a thick black malar
streak.
These sparrows feed primarily on seeds in the winter and insects in the spring and summer. The birds are often territorial, with males guarding their territory through song and displays. Flight is awkward for this species, which prefers to hop along the ground for locomotion. They are monogamous and breed during spring. Two to five eggs are laid in the bird's nest, which is cup-shaped and well hidden. Adult sparrows are preyed upon by house cats and small raptors
, while young may be taken by a range of mammals and reptiles. They have been known to live for up to three years, two months. Although the species has been classified as Least Concern
, or unthreatened with extinction, some subspecies are threatened by habitat destruction and one may be extinct.
, which consists of the American sparrows and Eurasian buntings
. The American sparrows are seed-eating New World birds with conical bills, brown or gray plumage, and distinctive head patterns. Birds in the genus Aimophila
tend to be medium-sized at 5 to 8 in (12.7 to 20.3 cm) in length, live in arid scrubland, have long bills and tails in proportion to their body size as well as short, rounded wings, and build cup-shaped nests.
The Rufous-crowned Sparrow was described in 1852 by American ornithologist John Cassin
as Ammodramus
ruficeps. It has also been described as belonging to the genus Peucaea, which contains several sparrows in the genus Aimophila that share characteristics, such as a larger bill and a patch of yellow under the bend of the wing, that other members of the genus do not. However, splitting the Peucaea sparrows into a separate genus is not generally recognized. A 2008 phylogenetic analysis of the genus Aimophila divided it into four genera, with the Rufous-crowned Sparrow and its two closest relatives, the Oaxaca Sparrow
and Rusty Sparrow
, being maintained as the genus Aimophila. In addition, this study suggested that the Rufous-crowned Sparrow may be more closely related to the brown towhee
s of the genus Pipilo than the other members of the historical genus Aimophila.
The derivation of the current genus name, Aimophila, is from the Greek
aimos/ἀιμος, meaning "thicket", and -philos/-φιλος, meaning "loving". The specific epithet is a literal derivation of the common name, derived from the Latin
rufus, meaning "reddish" or "tawny", and -ceps, from caput, meaning "head". The bird is also occasionally referred to colloquially as the Rock Sparrow because of its preference for rocky slopes.
The other six subspecies that are occasionally recognized are A. r. extima and A. r. pallidissima, which were described by A. R. Phillips in 1966, A. r. phillipsi, which was described by J.P. Hubbard and Crossin in 1974, and A. r. duponti, A. r. laybournae, and A. r. suttoni, which were described by J.P. Hubbard in 1975.
s 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 9800 feet (2,987 m), though it tends to be found between 3000 and 6000 ft (914.4 and 1,828.8 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.
of California ranges from 2 acre (0.809372 ha) to 4 acres (1.6 ha). The density of territories varies by habitat
, including 2.5 to 5.8 territories per 99 acres (40.1 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 Hawk
s, American Kestrel
s, and White-tailed Kite
s. 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. The head, neck and tail are lowered, wings held out, and feathers fluffed as the bird runs rapidly and voices a continuous alarm call. In the broken wing display, the sparrow imitates having a broken wing by dropping one to the ground and hopping away from the nest, leading the predator away until the bird ceases the act and escapes the predator. The adult Rufous-crowned Sparrow distracts a nest predator by falling from the top of a bush to attract the predator to itself in the tumbling off the bush display.
The longest lifespan recorded for a Rufous-crowned Sparrow is three years, two months. Two species of tick
, Amblyomma americanum
and Ixodes pacificus
, are known to parasitize the sparrow.
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 ant
s, grasshopper
s, ground beetle
s, and scale insect
s as well as spider
s 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.
The Rufous-crowned Sparrow forages slowly on or near the ground by walking or hopping under shrubs or dense grasses. Though it occasionally forages in weedy areas, it is almost never observed foraging in the open. It has occasionally been observed feeding in branches and low shrubs. During the breeding season, it gleans its food from grasses and low shrubs. However, normally the species obtains its food by either pecking or less frequently scratching at leaf litter. This bird tends to forage in a small family group and in a limited area.
It is unknown whether this species obtains all of the water it needs from its food or if it must also drink; however, it has been observed both drinking and bathing in pools of water after rain storms.
. 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.
While it is not known when precisely the breeding season starts, the earliest that a sparrow has been observed carrying nesting material was on March 2 in southern California. 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 (45.7 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, though some birds in California have been observed raising two or even three broods a year. In case of a nesting failure, replacement clutches may be laid. The eggs are an unmarked, pale bluish-white. Broods of the Rufous-crowned Sparrow have very occasionally been observed to be parasitized
by the Brown-headed Cowbird
.
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.
, or not threatened with extinction, by BirdLife International
due to its large geographical range of about 463323 mi2, estimated population of 2.4 million individuals, and lack of a 30% population decline over the last ten years. 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.
American sparrow
American sparrows are a group of mainly New World passerine birds, forming part of the family Emberizidae. American sparrows are seed-eating birds with conical bills, brown or gray in color, and many species have distinctive head patterns....
. This passerine
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
is primarily found across the Southwestern United States
Southwestern United States
The Southwestern United States is a region defined in different ways by different sources. Broad definitions include nearly a quarter of the United States, including Arizona, California, Colorado, Nevada, New Mexico, Oklahoma, Texas and Utah...
and much of the interior of Mexico, south to the transverse mountain range
Trans-Mexican volcanic belt
The Trans-Mexican Volcanic Belt also known as the Transvolcanic Belt and locally as the Sierra Nevada , is a volcanic belt that extends 900 km from west to east across central-southern Mexico...
, and to the Pacific coast to the southwest of the transverse range. Its distribution is patchy, with populations often being isolated from each other. Twelve subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
are generally recognized, though up to eighteen have been suggested. This bird has a brown back with darker streaks and gray underparts. The crown is rufous
Rufous
Rufous is a colour that may be described as reddish-brown or brownish-red, as of rust or oxidised iron.The first recorded use of rufous as a colour name in English was in the year 1782....
, and the face and supercilium
Supercilium
The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head. Also known as an "eyebrow", it is distinct from the eyestripe, which is a line which runs...
are gray with a brown or rufous streak extending from each eye and a thick black malar
Cheek
Cheeks constitute the area of the face below the eyes and between the nose and the left or right ear. They may also be referred to as jowls. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve...
streak.
These sparrows feed primarily on seeds in the winter and insects in the spring and summer. The birds are often territorial, with males guarding their territory through song and displays. Flight is awkward for this species, which prefers to hop along the ground for locomotion. They are monogamous and breed during spring. Two to five eggs are laid in the bird's nest, which is cup-shaped and well hidden. Adult sparrows are preyed upon by house cats and small raptors
Bird of prey
Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....
, while young may be taken by a range of mammals and reptiles. They have been known to live for up to three years, two months. Although the species has been classified as Least Concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
, or unthreatened with extinction, some subspecies are threatened by habitat destruction and one may be extinct.
Taxonomy
This bird belongs to the family EmberizidaeEmberizidae
The Emberizidae are a large family of passerine birds. They are seed-eating birds with a distinctively shaped bill.In Europe, most species are called buntings. In North America, most of the species in this family are known as sparrows, but these birds are not closely related to the sparrows, the...
, which consists of the American sparrows and Eurasian buntings
Bunting (bird)
Buntings are a group of Eurasian and African passerine birds of the family Emberizidae.They are seed-eating birds with stubby, conical bills, and are the Old World equivalents of the species known in North America as sparrows...
. The American sparrows are seed-eating New World birds with conical bills, brown or gray plumage, and distinctive head patterns. Birds in the genus Aimophila
Aimophila
Aimophila is a genus of American sparrows. The derivation of the genus name is from aimos/αιμος 'thicket' and phila/φιλα 'loving'.- Species in taxonomic order:* Stripe-capped Sparrow, Aimophila strigiceps...
tend to be medium-sized at 5 to 8 in (12.7 to 20.3 cm) in length, live in arid scrubland, have long bills and tails in proportion to their body size as well as short, rounded wings, and build cup-shaped nests.
The Rufous-crowned Sparrow was described in 1852 by American ornithologist John Cassin
John Cassin
John Cassin was an American ornithologist.He is considered to be one of the giants of American ornithology, and was America's first taxonomist, describing 198 birds not previously mentioned by Alexander Wilson and John James Audubon...
as Ammodramus
Ammodramus
The genus Ammodramus is a group of American sparrows in the family Emberizidae. Ammodramus is Latin for "Sand Runner." Typical of these thick grass and ground loving sparrows....
ruficeps. It has also been described as belonging to the genus Peucaea, which contains several sparrows in the genus Aimophila that share characteristics, such as a larger bill and a patch of yellow under the bend of the wing, that other members of the genus do not. However, splitting the Peucaea sparrows into a separate genus is not generally recognized. A 2008 phylogenetic analysis of the genus Aimophila divided it into four genera, with the Rufous-crowned Sparrow and its two closest relatives, the Oaxaca Sparrow
Oaxaca Sparrow
The Oaxaca Sparrow is a species of bird in the Emberizidae family.It is endemic to the Mexican state of Oaxaca, where it lives in dry forests and thornscrub.It is threatened by habitat loss.-References:...
and Rusty Sparrow
Rusty Sparrow
The Rusty Sparrow is a species of bird in the Emberizidae family.It is found in Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, and Nicaragua....
, being maintained as the genus Aimophila. In addition, this study suggested that the Rufous-crowned Sparrow may be more closely related to the brown towhee
Towhee
A towhee is any one of a number of species of birds in the genus Pipilo or Melozone within the family Emberizidae ....
s of the genus Pipilo than the other members of the historical genus Aimophila.
The derivation of the current genus name, Aimophila, is from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
aimos/ἀιμος, meaning "thicket", and -philos/-φιλος, meaning "loving". The specific epithet is a literal derivation of the common name, derived from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
rufus, meaning "reddish" or "tawny", and -ceps, from caput, meaning "head". The bird is also occasionally referred to colloquially as the Rock Sparrow because of its preference for rocky slopes.
Subspecies
Twelve subspecies are generally recognized, although sometimes up to eighteen are named.- 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 upperparts.
- A. r. canescens was described by American ornithologist W.E. Clyde ToddWalter Edmond Clyde ToddWalter Edmond Clyde Todd , generally known as W.E. Clyde Todd, was an American ornithologist....
in 1922, and it is found in southwestern California and northeast Baja CaliforniaBaja CaliforniaBaja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
as far east as the base of the San Pedro MartirSierra San Pedro MártirSierra de San Pedro Mártir is a mountain range that is one of the Peninsular Ranges of the Baja California peninsula, Mexico. At , the highest peak is the Picacho del Diablo, also known as Cerro de la Encantada or Picacho la Providencia...
. 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 GameCalifornia Department of Fish and GameThe California Department of Fish and Game is a department within the government of California, falling under its parent California Natural Resources Agency. The Department of Fish and Game manages and protects the state's diverse fish, wildlife, plant resources, and native habitats...
, signifying that this population is threatened with extinctionExtinctionIn biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
. 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 CaliforniaChannel Islands of CaliforniaThe Channel Islands of California are a chain of eight islands located in the Pacific Ocean off the coast of Southern California along the Santa Barbara Channel in the United States of America...
on Santa CruzSanta Cruz IslandSanta Cruz Island was the largest privately owned island off the continental United States, but is currently part-owned by the National Park service . The island, located off the coast of California, is long and from wide...
, AnacapaAnacapa IslandAnacapa Island is a small volcanic island located about off the coast of Port Hueneme, California, in Ventura County. The Island is composed of a series of narrow islets six miles long, running in a mostly east-west orientation, five miles east of Santa Cruz Island...
, and formerly on Santa CatalinaSanta Catalina Island, CaliforniaSanta Catalina Island, often called Catalina Island, or just Catalina, is a rocky island off the coast of the U.S. state of California. The island is long and across at its greatest width. The island is located about south-southwest of Los Angeles, California. The highest point on the island is...
. 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 IslandsIsla Todos SantosIsla Todos Santos is a pair of islands about 19.3km off Ensenada, Baja California at best known for surfing. Access is only by boat, which can be rented out from Ensenada, or La Bufadora. The waves off the smallest island are some of the biggest waves in the North American continent, rivaled in...
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 LagunaSierra de la LagunaThe Sierra de la Laguna is a mountain range on the Baja California Peninsula of Mexico. It lies at the southern end of the peninsula in the state of Baja California Sur, and is the southernmost range of the Peninsular Ranges....
. It is the palest of the coastal subspecies. - A. r. scottii, described by George Sennett in 1888, is found from northern ArizonaArizonaArizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
to New MexicoNew MexicoNew Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
south to northeastern SonoraSonoraSonora officially Estado Libre y Soberano de Sonora is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided into 72 municipalities; the capital city is Hermosillo....
and northwestern CoahuilaCoahuilaCoahuila, formally Coahuila de Zaragoza , officially Estado Libre y Soberano de Coahuila de Zaragoza is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico...
. 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. 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 NayaritNayaritNayarit officially Estado Libre y Soberano de Nayarit is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 20 municipalities and its capital city is Tepic.It is located in Western Mexico...
and northern JaliscoJaliscoJalisco officially Estado Libre y Soberano de Jalisco is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is located in Western Mexico and divided in 125 municipalities and its capital city is Guadalajara.It is one of the more important states...
. 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, TexasTexasTexas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, northern Chihuahua, and central Coahuila. It has grayish upperparts and a dark breast. - A. r. fusca, described by Edward William NelsonEdward William NelsonEdward William Nelson was an American naturalist and ethnologist. He was born in Manchester, New Hampshire. In 1871 together with his family, he became homeless due to the Chicago Fire....
in 1897, is found in western Mexico from southern Nayarit to southwestern Jalisco, northern ColimaColimaColima is one of the 31 states which, with the Federal District, make up the 32 Federal Entities of Mexico. It shares its name with its capital and main city, Colima....
, and MichoacanMichoacánMichoacán officially Estado Libre y Soberano de Michoacán de Ocampo is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 113 municipalities and its capital city is Morelia...
. It is darker and more rufous on its upperparts 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 SclaterPhilip SclaterPhilip Lutley Sclater was an English lawyer and zoologist. In zoology, he was an expert ornithologist, and identified the main zoogeographic regions of the world...
in 1867, and it is found in eastern Mexico from southern Coahuila to San Luis PotosíSan Luis PotosíSan Luis Potosí officially Estado Libre y Soberano de San Luis Potosí is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 58 municipalities and its capital city is San Luis Potosí....
, northern PueblaPueblaPuebla officially Estado Libre y Soberano de Puebla is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 217 municipalities and its capital city is Puebla....
, and southern OaxacaOaxacaOaxaca , , officially Estado Libre y Soberano de Oaxaca is one of the 31 states which, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided into 571 municipalities; of which 418 are governed by the system of customs and traditions...
. 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 GuerreroGuerreroGuerrero officially Estado Libre y Soberano de Guerrero is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 81 municipalities and its capital city is Chilpancingo....
to southern Puebla and Oaxaca. A. r. scottii is similar in appearance, but this subspecies is smaller and has a shorter bill.
The other six subspecies that are occasionally recognized are A. r. extima and A. r. pallidissima, which were described by A. R. Phillips in 1966, A. r. phillipsi, which was described by J.P. Hubbard and Crossin in 1974, and A. r. duponti, A. r. laybournae, and A. r. suttoni, which were described by J.P. Hubbard in 1975.
Description
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 grams (0.53 to 0.81 oz) in weight and averages about 19 grams (0.67 oz). It has a brown back with darker streaks and gray underparts. Its wingWing
A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...
s 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
Supercilium
The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head. Also known as an "eyebrow", it is distinct from the eyestripe, which is a line which runs...
(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
Crown (anatomy)
A crown is the top of the head.The following birds and other animals are said to have a crown on their head:* Cranes** Grey-crowned Crane** Red-crowned Crane** Black-crowned Crane* Crowned eagle* Gray-crowned Rosy Finch* Yellow-crowned Gonolek...
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.
Distribution and habitat
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, southern Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, southern New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
, Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, and central Oklahoma
Oklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...
south along Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
and in western Mexico to southern Puebla
Puebla
Puebla officially Estado Libre y Soberano de Puebla is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 217 municipalities and its capital city is Puebla....
and Oaxaca
Oaxaca
Oaxaca , , officially Estado Libre y Soberano de Oaxaca is one of the 31 states which, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided into 571 municipalities; of which 418 are governed by the system of customs and traditions...
. In the midwestern United States
Midwestern United States
The Midwestern United States is one of the four U.S. geographic regions defined by the United States Census Bureau, providing an official definition of the American Midwest....
, the sparrow is found as far east as a small part of western Arkansas
Arkansas
Arkansas is a state located in the southern region of the United States. Its name is an Algonquian name of the Quapaw Indians. Arkansas shares borders with six states , and its eastern border is largely defined by the Mississippi River...
, and also in a small region of northeastern Kansas
Kansas
Kansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south...
, 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
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
species, though the mountain subspecies are known to descend to lower elevations during severe winters. Male sparrows maintain and defend their territories
Territory (animal)
In ethology the term territory refers to any sociographical area that an animal of a particular species consistently defends against conspecifics...
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
Chaparral
Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...
areas. The Rufous-crowned Sparrow thrives in open areas cleared by burning.
Ecology and behavior
The average territory size of Rufous-crowned Sparrows in the chaparralChaparral
Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...
of California ranges from 2 acre (0.809372 ha) to 4 acres (1.6 ha). The density of territories varies by habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
, including 2.5 to 5.8 territories per 99 acres (40.1 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
Cooper's Hawk
Cooper's Hawk is a medium-sized hawk native to the North American continent and found from Canada to Mexico. As in many birds of prey, the male is smaller than the female...
and Sharp-shinned Hawk
Sharp-shinned Hawk
The Sharp-shinned Hawk is a small hawk. In fact, "sharp-shins" or "sharpies" are the smallest to reside in USA and Canada, though some Neotropical species are smaller...
s, American Kestrel
American Kestrel
The American Kestrel , sometimes colloquially known as the Sparrow Hawk, is a small falcon, and the only kestrel found in the Americas. It is the most common falcon in North America, and is found in a wide variety of habitats. At long, it is also the smallest falcon in North America...
s, and White-tailed Kite
White-tailed Kite
The White-tailed Kite is an elanid kite of genus Elanus found in western North America and parts of South America.Their coloration is gull-like, but their shape and flight falcon-like, with a rounded tail...
s. 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
Distraction display
Distraction displays, also known as deflection display, diversionary display or paratrepsis, are anti-predator behaviours used to attract the attention of an enemy away from an object, typically the nest or young, that is being protected. They are particularly well known in birds but noted also in...
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. The head, neck and tail are lowered, wings held out, and feathers fluffed as the bird runs rapidly and voices a continuous alarm call. In the broken wing display, the sparrow imitates having a broken wing by dropping one to the ground and hopping away from the nest, leading the predator away until the bird ceases the act and escapes the predator. The adult Rufous-crowned Sparrow distracts a nest predator by falling from the top of a bush to attract the predator to itself in the tumbling off the bush display.
The longest lifespan recorded for a Rufous-crowned Sparrow is three years, two months. Two species of tick
Tick
Ticks are small arachnids in the order Ixodida, along with mites, constitute the subclass Acarina. Ticks are ectoparasites , living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians...
, Amblyomma americanum
Amblyomma americanum
Amblyomma americanum, or lone star tick, is a species of tick in the genus Amblyomma. It's average length is 1/4 inch.-Distribution:...
and Ixodes pacificus
Ixodes pacificus
Ixodes pacificus, the Western blacklegged tick, is a species of Ixodes, a parasitic tick found on the western coast of North America. It is the principal vector of Lyme Disease in that region....
, are known to parasitize the sparrow.
Diet
Forb
A forb is a herbaceous flowering plant that is not a graminoid . The term is used in biology and in vegetation ecology, especially in relation to grasslands and understory.-Etymology:...
seeds, fresh grass stems, and tender plant shoots during autumn and winter. During these seasons, insects such as ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
s, grasshopper
Grasshopper
The grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as the short-horned grasshopper...
s, ground beetle
Ground beetle
Ground beetles are a large, cosmopolitan family of beetles, Carabidae, with more than 40,000 species worldwide, approximately 2,000 of which are found in North America and 2,700 in Europe.-Description and ecology:...
s, and scale insect
Scale insect
The scale insects are small insects of the order Hemiptera, generally classified as the superfamily Coccoidea. There are about 8,000 species of scale insects.-Ecology:...
s as well as spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
s 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.
The Rufous-crowned Sparrow forages slowly on or near the ground by walking or hopping under shrubs or dense grasses. Though it occasionally forages in weedy areas, it is almost never observed foraging in the open. It has occasionally been observed feeding in branches and low shrubs. During the breeding season, it gleans its food from grasses and low shrubs. However, normally the species obtains its food by either pecking or less frequently scratching at leaf litter. This bird tends to forage in a small family group and in a limited area.
It is unknown whether this species obtains all of the water it needs from its food or if it must also drink; however, it has been observed both drinking and bathing in pools of water after rain storms.
Reproduction
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 seasonBreeding season
The breeding season is the most suitable season, usually with favourable conditions and abundant food and water, for breeding among some wild animals and birds . Species with a breeding season have naturally evolved to have sexual intercourse during a certain time of year in order to achieve the...
. 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.
While it is not known when precisely the breeding season starts, the earliest that a sparrow has been observed carrying nesting material was on March 2 in southern California. 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 (45.7 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, though some birds in California have been observed raising two or even three broods a year. In case of a nesting failure, replacement clutches may be laid. The eggs are an unmarked, pale bluish-white. Broods of the Rufous-crowned Sparrow have very occasionally been observed to be parasitized
Brood parasite
Brood parasites are organisms that use the strategy of brood parasitism, a kind of kleptoparasitism found among birds, fish or insects, involving the manipulation and use of host individuals either of the same or different species to raise the young of the brood-parasite...
by the Brown-headed Cowbird
Brown-headed Cowbird
The Brown-headed Cowbird is a small brood parasitic icterid of temperate to subtropical North America. They are permanent residents in the southern parts of their range; northern birds migrate to the southern United States and Mexico in winter, returning to their summer habitat around March or...
.
Incubation
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...
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
El Niño-Southern Oscillation
El Niño/La Niña-Southern Oscillation, or ENSO, is a quasiperiodic climate pattern that occurs across the tropical Pacific Ocean roughly every five years...
years, since cool rainy weather reduces the activity of snakes, the main predator of the sparrow’s nests.
Conservation
The Rufous-crowned Sparrow is treated as a species of Least ConcernLeast Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
, or not threatened with extinction, by BirdLife International
BirdLife International
BirdLife International is a global Partnership of conservation organisations that strives to conserve birds, their habitats and global biodiversity, working with people towards sustainability in the use of natural resources...
due to its large geographical range of about 463323 mi2, estimated population of 2.4 million individuals, and lack of a 30% population decline over the last ten years. 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
Warfarin
Warfarin is an anticoagulant. It is most likely to be the drug popularly referred to as a "blood thinner," yet this is a misnomer, since it does not affect the thickness or viscosity of blood...
, though more research is needed to determine the effects of pesticides on the Rufous-crowned Sparrow.
Theses
- Groschupf, K. D. Ph.D. (1983). Comparative study of the vocalizations and singing behavior of four Aimophila sparrows. Virginia Polytechnic Institute and State University, United States.
- Morrison, S. A. Ph.D. (2001). Demography of a fragmentation-sensitive songbird: Edge and ENSO effects. Dartmouth College, United States.
- Wimer, M. C. M.S. (1995). Song variation in insular and mainland Rufous-crowned Sparrows. California State University, Long Beach, United States. California.
External links
- Call recordings
- Rufous-crowned Sparrow photo gallery VIREO
- Rufous-crowned Sparrow videos on the Internet Bird Collection
- Old illustration from Cassin's Birds of California and Texas