Cactus Wren

识别特征

The cactus wren is the largest wren in the United States. It is between 18 and 19 cm (7.1 and 7.5 in) long, and weighs between 33.4 and 46.9 g (1.18 and 1.65 oz), with an average of 38.9 g (1.37 oz).: 207  It has a thick, heavy bill that is dull black, curves slightly downwards, and is about the same length as the head. The lower mandible is grayish and pale, and the tail is long and rounded.: 207 <p>The cactus wren's coloration is brown with white speckles. The crown is chocolate-brown with a light red tinge. A distinctive white supercilium (eyebrow) runs from the bill to the nape of its neck, which is brown with white markings. The chin is white, while the neck has black markings on a mostly white background. Their chest is white with brown or black speckles, and the belly is generally white with some brown or black streaks. The rump and back are gray to brown with white and black streaks. Both the lower underparts and the flanks are cinnamon-buff colored.<p>The cactus wren's ten primary and nine secondary flight feathers are barred, alternating between black and off-white. Its twelve rectrices are barred, alternating between brownish-black and pale gray-brown. The outer rectrices are white tipped. When flying, a white band can be seen on the underside of the tail feathers. The tail is barred in alternating stripes of black, white, and brown. The legs are brown to pink-brown.<p>Males and females look alike; juveniles can be distinguished by their paler coloration and red-brown to muddy-gray eyes. Adults have more red-brown to red eyes. Other distinctive features of juveniles include the lack of a white nape streak, and less noticeable black chest markings. Summer often takes a harsh toll on plumage; the intense desert sun and prickly vegetation fade and damage feathers. This wear and tear can make identification of juveniles more difficult. Worn feathers are replaced by molting, which happens in adults from July through October, usually in the bird's own territory. Not all feathers will molt in a single season.<p>Although the cactus wren looks similar to other wrens in its genus, cactus wren identification is made easier since the habitat of Campylorhynchus wrens does not overlap. A notable difference that can assist in identification of the cactus wren is the white tail band seen in flight. The spotted wren looks similar, but is paler and has fewer markings, and its habitat is in oak woodlands (where cactus wrens do not usually live).<p>The main call of the cactus wren is a harsh and raspy series of jar-jar-jar, or char, notes, which increase in volume and pitch as the song goes on. Each part of the call lasts around four seconds, with four to eight seconds between calls; calls can carry up to 300 metres (1,000 ft). Cornell University ornithologists described it as sounding "like a car that just won't start". Males are the primary singers, although females can also sing – their song is weaker and higher pitched. Males begin singing before dawn and prefer to vocalize from high vantage points, such as trees, telephone poles, tall cacti, or roofs. At least eight other songs exist besides the main call. A buzz or tek is given as a warning call. Growls serve as a mating and identification call. Rack calls are used for locating an existing mate, or other wrens – this call is often the first vocalization made upon leaving the nest. A high pitched "squeal" is given only during nest building, and is heard rarely. Scri notes are let out during territorial disputes with other wrens. Chicks make various begging vocalizations, including a soft peep. A dzip call is known to be made exclusively by fledglings. The main call is made while the beak is held just slightly above horizontal, and makes the feathers on the bird's throat noticeably extend from their normal position and vibrate.: 32

分类信息

The wren family is a group of generally small passerine birds, found – with one exception – only in the New World. Although the cactus wren is the largest wren in the U.S., globally the title is shared between the giant wren and the bicolored wren. It was historically considered conspecific (of the same species) with the Yucatan wren and Boucard's wren, but there are numerous morphological and behavioral differences between the species. A 2007 genetic study by Barker indicated that all three were distinct species. Work on wren taxonomy in the 20th century postulated that the Yucatan, Boucard's, and cactus wrens – along with the spotted wren – might constitute a superspecies. The 2007 study showed this to be unlikely, as the cactus wren was found to be ancestral to the other species. Study of the evolution of the cactus wren suggests that it evolved in central Mexico about one million years ago and quickly spread to its modern range.<p>The first description of a cactus wren was in 1835 by ornithologist Frédéric de Lafresnaye. Lafresnaye was a Frenchman who never visited America; his specimen was gifted to him by ornithologist and businessman Charles Brelay. Brelay procured the specimen from a naval officer who had recently returned from California. It is likely that the bird was picked up at the port of Guaymas, in Sonora. However, Lafresnaye did not know that, and thought the specimen – which he called Picolaptes brunneicapillus – might have come from Peru (far outside the range of the wren), as the officer had stopped there on his journey. The unclear geographic origin contributed to much ensuing taxonomic confusion. Because the original description of the wren had been geographically imprecise, ornithologists described the cactus wren multiple times as different species; incorrect descriptions happened until as late as 1898. Subspecies were also incorrectly described as independent species. Matters were not helped by ornithologist John Gould, who described the cactus wren – as Thryothorus guttatus – independently in 1836 and also failed to say precisely where his specimen had come from. Lafresnaye renamed Gould's find Campylorhynchus guttatus in 1846, still not realizing they had described the same bird. Although ornithologist Spencer Baird suggested in 1864 that Lafresnaye and Gould's birds might be the same, Lafresnayes and Gould's separate descriptions continued to be used until 1945, when it was determined that they were different subspecies of the same bird. The cactus wren was placed in the genus Helodytes by the American Ornithologists' Union in 1894, but they returned it to Campylorhynchus in 1947.: 212–215 <p>The genus name Campylorhynchus is Greek, and roughly translates to 'curved beak'. The specific epithet brunneicapillus translates as 'brown hair', referring to the bird's brown head and back. The bird's common name comes from its frequent use of cacti as nesting sites, its association with cacti,: 1  as well as the use of cacti for perches, roosting, and seeking protection from predators.<p>The 2007 study by Barker established the relationships between the cactus wren and related wrens in the genus Campylorhynchus, including select subspecies. Those relations are summarized in the following cladogram:<p>Various subspecies of the cactus wren have been described, and seven are generally recognized. The exact taxonomy of the cactus wren remains under debate, and not all subspecies are universally recognized. Ornithologists Anders and Anne Anderson, in their compendium of 40 years of cactus wren research published in 1973, recognize seven subspecies and do not classify C. b. sandiegensis as an independent subspecies.: 211  The International Ornithologists' Union recognizes seven subspecies – including C. b. sandiegensis – but does not recognize C. b. purus. Below are all proposed subspecies:

学名

Campylorhynchus brunneicapillus

命名信息

(Lafresnaye, 1835)

目

Passeriformes

科

Troglodytidae

属

Campylorhynchus

分布与栖息地

The cactus wren is a bird of arid and semi-desert regions, and generally requires spiny cacti to nest in. Its range includes the Sonoran and Chihuahuan Deserts. The cactus wren is not migratory, and establishes a permanent territory which it defends vigorously. Territories are typically 1.3 ha (3.2 acres) to 1.9 ha (4.7 acres). The size and shape of territories change very little throughout the season.: 18  Territory is defended from other birds by fluffing tails and feathers and vocal scolding. Persistent trespassers may cause the wrens to give chase.<p>The cactus wren is found only in the United States and Mexico. In the U.S., it is present in California, Nevada, Utah, Arizona, New Mexico, and Texas. In California, it is found mainly as southern coastal populations existing below 600 m (2,000 ft), but some have been found up to 950 m (3,120 ft). Nevada represents the northernmost extent of its range; it is found in the southern tip of the state and the northernmost breeding population is found in Nye County, near Tonopah. In Utah, it is found only in the extreme southwest. Its range in Arizona is widespread in the southern part of the state and along the Colorado River, where it is found from sea-level up to 1,400 m (4,600 ft). Populations in New Mexico exist in the south, down to along the Rio Grande and into Mexico. Its range in both New Mexico and Texas may be expanding northward. Texas cactus wrens live between sea-level and 1,800 m (5,900 ft) throughout the Texas Panhandle, Central Texas, and as far east as Travis County. In Mexico, it is found in Sinaloa, Sonora, Chihuahua, Coahuila, Nuevo León, Hidalgo, and throughout Baja California. On the Central Mexican plateau and in New Mexico, it is found up to 2,000 m (6,600 ft). Populations may be expanding their range in Baja California, but they are not found in the mountains or interior of Baja.

迁徙

Resident species

行为

Migration pattern: Resident species.

保护状况

Population trend: declining.

种群趋势

declining