Bell's Vireo
Vireo bellii
A fairly drab vireo of dense, scrubby vegetation, often near water. Two populations: Eastern birds are brighter, with yellow flanks and olive-green back. Note vague spectacled pattern around eye and one bright white wingbar (sometimes with a fainter upper wingbar). Western birds vary from dull olive above to entirely plain gray, usually with one bright wingbar. Look for long tail, often cocked and flipped around. Very active, flitting around nervously in low bushes and thickets. Listen for fast, scratchy song and harsh scold notes. Compare with the brighter and more contrasty White-eyed Vireo, especially in the East, and with the larger and plainer Gray Vireo in the West.
识别特征
Measurements:
分类信息
- 学名
- Vireo bellii
- 命名信息
- Audubon, 1844
- 目
- Passeriformes
- 科
- Vireonidae
- 属
- Vireo
分布与栖息地
- 迁徙
- Complete migrants
行为
Bell's vireos often use dense shrubbery including willows (Salix spp.), mulefat (Baccharis glutinosa), California wild rose (Rosa californica), mugwort (Artemisia douglasiana), Fremont cottonwood (Populus fremontii), and Western poison oak (Toxicodendron diversilobum) shrubs or vines as nesting locations. Bell's vireos make a well-camouflaged nest but when found they will stand its ground against intruders. As with many other North American songbirds, brown-headed cowbirds parasitise Bell's vireo nests, letting the vireos raise their young.<p>Historically, the least Bell's vireo was a common to locally abundant species in lowland riparian habitat, ranging from coastal southern California through the Sacramento and San Joaquin Valleys as far north as Red Bluff in Tehama County. Populations also occurred in the foothill streams of the Sierra Nevada and Coast Ranges, and in Owens Valley, Death Valley, and scattered locations in the Mojave Desert. Least Bell's vireos winter in Baja California Peninsula. Unlike during the breeding season, they are not limited in winter to willow-dominated riparian areas, but occupy a variety of habitats including mesquite scrub within arroyos, palm groves, and hedgerows bordering agricultural and residential areas. At the time of endangered species listing by the U.S. Fish and Wildlife Service in 1986, it had been extirpated from most of its historic range, and numbered just 300 pairs statewide. Populations were confined to eight counties south of Santa Barbara, with the majority of birds occurring in San Diego County. In the decade since listing, least Bell's vireo numbers have increased six-fold, and the species is expanding into its historic range. In 1998, the population size was estimated at 2,000 pairs. Nesting least Bell's vireos have recolonized the Santa Clara River in Ventura County, where 67 pairs nested in 1998, and the Mojave River in San Bernardino County. The northernmost reported sighting in recent years is of a nesting pair of least Bell's vireos near Gilroy in Santa Clara County in 1997. Roughly half of the current least Bell's vireo population occurs on drainages within Marine Corps Base Camp Pendleton in San Diego County, particularly in the lower Santa Margarita River.
保护状况
- 种群趋势
- rising
照片
分布
鸟叫声
其他鸟类
Long-tailed Honey-buzzard
Henicopernis longicauda
A large, long-tailed raptor of lowland and montane forest and clearings. Commonly seen in flight soaring in circles over the canopy with wing and tail feathers spread, showing strong barring. The only similar looking raptor that regularly soars is Pacific Baza, but Long-tailed Honey-buzzard has a streaked chest and lacks the buffy underwing and belly. When perched, similar to Doria’s Goshawk, but has yellow eyes and white legs. Usually silent.
Himalayan Swiftlet
Aerodramus brevirostris
Gray-brown swiftlet with a pale gray rump and a squared-off tail. The westernmost ranging species in the genus and the only member throughout much of its range. Smaller than most other swifts in range except for House Swift, which is black overall with a sharp white rump and throat. Tends to travel in small to medium-sized flocks, often swooping low over bodies of water. Builds dark bowl-shaped nests in closely-clustered colonies under rocky overhangs, in caves, and in old buildings. Gives clicking calls and twitters, especially when near colonies.
Wetar Ground Dove
Pampusana hoedtii
A fairly large ground-dwelling forest dove. Male is mostly dark with a diagnostic pale head and breast. Upperparts are rufous-brown, head pale gray, belly blackish-brown, and throat, neck, and breast cream-colored. Female entirely brown, with head, neck, and tail considerably more rufous than rest of body. Singles and small groups inhabit forested lowlands on Timor and Wetar islands. Female distinguished from Little and Timor Cuckoo-Doves by shorter tail, dark eyes, and absence of barring. The species gives a two-note hooting call with a short introductory note and an upslurred second one: “wu-wOOYOOP.”
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