Chihuahuan Raven
Corvus cryptoleucus
The raven of dry grasslands and desert scrub from the southwestern U.S. to central Mexico. Very similar to Common Raven, and sometimes best left unidentified. Chihuahuan is slightly smaller and more compact than Common, and tends to be found in more open habitats at lower elevations, not in mountains or forests (although Common can be found in low grasslands, too). Neck feathers are white at the base on Chihuahuan, instead of gray. Occurs in pairs or flocks, sometimes quite large, especially in winter. Gives a rather dry, crow-like squawk.
识别特征
The proportions resemble the common raven with a heavy bill, but is about the same size as a carrion crow, or slightly larger than the American crow (44–51 cm (17–20 in) long). The plumage is all-black with a rich purple-blue gloss in good light. Like the forest raven, little raven, fan-tailed raven and Australian raven, it is one of the smaller raven species. The larger species of raven are the common raven, thick-billed raven, white-necked raven and brown-necked raven, with the common and thick-billed ravens being the world's largest raven species and the little and fan-tailed ravens being the smallest. The Chihuahuan raven is similar in appearance to the Australian raven, although with dark brown irises and whiter feather bases. The nasal bristles extend farther down the top of the bill than in any other Corvus species to about two-thirds the length. In addition, the Chihuahuan raven is similar in appearance to the white-necked raven of east Africa because the base of the neck has feathers that are white-ish (seen only when ruffled in strong wind). The bill, legs and feet are black.
分类信息
A 2005 molecular study reviewed segments of DNA of the common raven and found that Chihuahuan raven are genetically nested within common ravens based on mitochondrial DNA. That is, common ravens from the California clade are more similar in mtDNA to Chihuahuan ravens than they are to common ravens in the Holarctic Clade.
- 学名
- Corvus cryptoleucus
- 命名信息
- Couch, 1854
- 目
- Passeriformes
- 科
- Corvidae
- 属
- Corvus
分布与栖息地
The Chihuahuan raven occurs in the Southwestern and Midwestern United States and northern Mexico, including southeastern Arizona, southern New Mexico, southeastern Colorado, western Kansas, western Oklahoma, and southern and western Texas.
- 迁徙
- Complete migrants
行为
It feeds on cultivated cereal grains, insects and many other invertebrates, small reptiles, carrion, cactus fruits, eggs and nestlings.<p>The nest is built in either trees, large shrubs or sometimes even in old buildings. There are usually 5–7 eggs laid relatively late in the year during May so as to take advantage of the insect food for their young in their more arid environment. Both the males and females incubate the eggs, feed the young, and remain territorial in protecting the nesting area. In rare cases, outsiders may be allowed into the territory to communally defend against potential predators.<p>The voice is similar to that of the common raven with "pruk-pruk" sounds and other croaks at slightly higher pitches. Like all corvids, the Chihuahuan raven is capable of vocal mimicry, however this behavior is mostly recorded in captivity and rarely in the wild.
保护状况
- 种群趋势
- stable
照片
分布
鸟叫声
其他鸟类
Sao Tome Grosbeak
Crithagra concolor
A large uniform chestnut finch with a robust pink-horn bill. Endemic to São Tomé and very rare; once thought to be extinct. Found singly and in pairs in primary and secondary forest in remote highlands where good habitat persists. Prefers the middle levels of the forest, but is also occasionally encountered on the ground. Loud human-like whistles, upslurred and high-pitched, “weeeooo” or “wheeet-wheeeoo,” are often the first sign of its presence. The Principe seedeater is much smaller and duller in coloration than Sao Tome Grosbeak.
Spot-breasted Parrotbill
Paradoxornis guttaticollis
A bulbous-headed brown bird with a comically large bill. Brownish overall, with a rich chestnut cap and paler underparts. Face is liberally splattered with black splotches, the largest patch on the ear where it forms a thick crescent. Pale yellow bill is oddly twisted, making it seem as if the bird is smiling. Prefers brushy habitats with dense cover, including bamboo stands and heavily overgrown field edges, in foothills up to montane areas. Joins mixed flocks. Can be difficult to see in thick cover, but will perch up to sing. Song a repetitive “aw-wi-WI-WI-Wi-WI” whose pitch and cadence may vary.
Bananal Antbird
Cercomacra ferdinandi
An antbird with a very restricted distribution in the Araguaia Valley. Males are black with white wing bars and white tips to the tail, while females are similar but gray and slightly streaked on the breast. Occurs in gallery forest and adjacent second growth, where it forages in the understory and does not join mixed-species flocks. Males give a series of staccato notes and are sometimes joined in a duet by females giving high-pitched notes.
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