Nuttall's Woodpecker
Dryobates nuttallii
Small woodpecker almost entirely restricted to the state of California (barely entering northern Baja). Look for black-and-white barring on the back and patterned flanks. Males have a red cap, often raised and fluffy-looking. Occurs in oak woodlands and riparian areas, sometimes visiting bird feeders. Most similar to Ladder-backed Woodpecker, but range barely overlaps. Also compare with Downy Woodpecker, which has clean flanks and lacks bars on the back.
识别特征
Nuttall's woodpecker has black wings and tail feathers with white barring. On the ventral surface, colour is white with black spots and barring. It has a black forehead with white streaks on the sides and an unbarred black region at the top of the back. Adult males have a distinguishable red crown which females do not. However, this physical feature is present in the juvenile of both sexes. They have zygodactyl feet and stiff tail feathers which allows them to maintain a vertical position on trees; typical of woodpeckers. The mass of the Nuttall's woodpecker ranges from 30 to 45 g (1.1 to 1.6 oz), with a body length of 16 to 18 cm (6.3 to 7.1 in).
分类信息
The Nuttall's woodpecker is closely related to the ladder-backed woodpecker of Arizona, New Mexico, Texas, and Mexico.[page needed][full citation needed] The Nuttall's likely evolved via allopatric speciation when the two species were separated into smaller ranges by dry climate during the Pleistocene glaciation.[page needed] Hybrids of the two species exist but are rare.[page needed]
- 学名
- Dryobates nuttallii
- 命名信息
- (Gambel, 1843)
- 目
- Piciformes
- 科
- Picidae
- 属
- Dryobates
分布与栖息地
Nuttall's are a non-migratory species with a geographic range confined to northern California extending south towards the northwest region of Baja California, Mexico. Their preferred habitat is arid to mesic woodlands. In particular, these woodpeckers prefer oak woodlands, although they also occur in riparian sites and chaparral in the most southern parts of its range because of the decrease in oak abundance. Individuals are found from sea level to 1,250 m (4,100 ft), rarely to 2,000 m (6,600 ft).[page needed] Although they have been found as far east as Central Wyoming.<p>The birds are not considered globally threatened although the range is restricted to the California Endemic Bird Area.[page needed] They are fairly common in California with a total world population estimated at over 100,000 individuals (density of about 20 birds per square kilometer in San Bernardino County).[page needed] Surveys suggest no obvious population trends.[page needed]
- 迁徙
- Resident species
行为
Vocalizations performed by Nuttall's woodpecker are considered to be not of any harmonic. Some vocalizations have been described:<p>Both sexes drum. Rolls are relatively long, averaging over one second.[page needed]<p>Nuttall's woodpecker feeds primarily on insect larvae such as those of wood borers, click beetles, and ants, found by tapping and probing into the crevices in oak trees. The bird also feeds on sap from sap holes created by red-breasted sapsuckers in birch and willow, and consumes a variety of berry seeds.<p>Pair bonding occurs in late January to March with egg-laying mostly in April and May. Nuttall's woodpeckers are socially monogamous and show displays of bi-parental care. New nests are excavated each year by males in the cavities of dead trees such as willow, oak, and alder. Clutch sizes range from three to six eggs with the male partner incubating the eggs at night and the female during the day. Incubation period can be up to 14 days. Fledglings are able to leave the nest around 29 days post hatch with parental care continuing for 14 days after that.
保护状况
- 种群趋势
- rising
照片
分布
鸟叫声
其他鸟类
Key West Quail-Dove
Geotrygon chrysia
A smallish, chunky, ground-dwelling species of dense woodlands with thick leaf litter; prefers drier habitats. Secretive but not shy; sometimes detected by the rustling of leaves it is strolling through. The rather similar Bridled Quail-Dove is dull brown rather than reddish or purple on the upper back and it has iridescent turquoise on the sides of its neck. Ruddy Quail-Doves have less contrast in facial markings and the males have an entirely rusty back; some also sport a vertical white shoulder stripe. The Blue-headed Quail-Dove has a blue crown and bib. This species’ song is a soft, low plaintive “hooooooo,” given at a single pitch, but growing gradually louder before dropping off abruptly at the end.
Little Rock-Thrush
Monticola rufocinereus
A small rock-thrush with blue-gray upperparts and hood and an orange belly. The tail has a black-and-orange “T” pattern that is conspicuous in flight. Males and females vary slightly: males are cleaner blue-gray above, while females are more brownish. Found locally in a variety of habitats with a mix of rocks, trees, and bushes. Sometimes also on and around human structures. Similar to redstarts, but easily distinguished by the clean gray hood and the lack of black on the face. Also similar to male Rufous-tailed Rock-Thrush, but smaller, lacking white on the back, and with a more extensive gray hood. The quiet song consists of musical phrases that can be short or quite long.
Daurian Redstart
Phoenicurus auroreus
Active and attractive songbird of open spaces. Breeds in open forests and scrubby vegetation in subalpine areas; winters in a wider altitudinal range in scrubby forest edges, gardens, and fields. Frequently bobs the orange-sided dark tail. Male sports a gray crown and nape, black face, orange underparts, and dark wings with a white wing patch. Females are brownish overall but share the male's bright tail and wing patch. Compare carefully with Common, Hodgson’s, and Black Redstarts. Song is a lively, jingling cascade of warbling; calls include a short, high-pitched whistle and a hard “tsak.”
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