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.
Identification
Measurements:
Taxonomy
- Scientific name
- Vireo bellii
- Authority
- Audubon, 1844
- Order
- Passeriformes
- Family
- Vireonidae
- Genus
- Vireo
Range and habitat
- Migration
- Complete migrants
Behavior
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.
Conservation
- Population trend
- rising
Photos
Distribution
Bird Calls
Other Birds
Sand-colored Nighthawk
Chordeiles rupestris
Light-colored nighthawk of Amazonian rivers. Tan with fine patterning and largely white underparts. Appears evenly tan when perched, blending in with the beach or branch it is perched on; in flight, broad white wing stripe and white breast and belly contrast highly with black areas. Roosts on beaches and exposed branches and logs along rivers, foraging for insects low over beaches and rivers and sometimes higher in the sky, usually at dusk. Often roosts and forages in large flocks, occasionally upwards of 100 individuals. Similar only to Nacunda Nighthawk, which is much larger with broader wing tips, and a distinct white wing band on each wing contrasting with black wing tip (not a large wedge of white as in Sand-colored).
Selva Cacique
Cacicus koepckeae
Rare cacique found very locally in lowland forest in southeastern Peru and extreme SW Brazil, especially near forest-fringed lakes and rivers. Note yellow rump and pale blue eye, which separate it from Solitary Black Cacique. Told from Yellow-rumped Cacique by the yellow being limited to the rump in Selva. No overlap with the closely related Ecuadorian Cacique. It has a varied vocal repertoire, with whistles, metallic squeaks, and various buzzing notes, among other calls.
Cream-throated White-eye
Zosterops atriceps
A tiny warbler-like songbird with a pale eye-ring. Greenish above and grayish-white below with a yellow undertail and variable amounts of black on the front of the head. Singles, pairs, or groups inhabit forest, edge, and cultivated areas in lowlands and hills. Confined to Halmahera, Obi, and Bacan. Separated from Warbling White-eye by whitish or gray underparts. Gives a high-pitched twittering song, characteristic of white-eyes.
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