Emberizidae (Emberizids). Parulinae (Wood Warblers)

Orange-crowned Warbler,Vermivora celata . (Fig. 11.43) Male length 4 2/5 in (11.25 cm), female length 4 5/8 in (11.75 cm); male weight 2/5 oz (9.2 g), female weight 2/5 oz (9.1 g). Relatively common summer resident in the White Mountains and locally in the Inyo Mountains, between 6,650 and 9,500 ft (2,030 and 2,900 m).

The interior form of this species lives only in moist canyon bottoms, in the cool riparian strip of aspen, Water Birch, and associated thickets of willow and Wild Rose. Such habitat contrasts greatly with the warm Oak-Chaparral growth at low elevations occupied by the form on the west side of the Sierra Nevada. Like most other species in the genus Vermivora , the Orange-crowned Warbler builds its nest in a concealed place on the ground. The adults are well hidden as they search for insects and spiders in the foliage of willow, rose, and aspen saplings. Most challenging of all is to pinpoint the male as he sings from the crowns of aspen, birch, or willow along the stream. His song — a continuous, insectlike trill of two or three parts, each on a slightly different pitch — is usually delivered in long series from a concealed perch. Although exposed briefly while flying between song perches, he quickly vanishes again in the leafy treetops. References: Mengel (1964), Morrison (1981).

Virginia's Warbler,Vermivora virginiae . (Fig. 11.44) Male length 4 1/4 in (11 cm), female length 4 1/4 in (11 cm); male weight 2/5 oz (8.4 g), female weight 1/4 oz (7.5

Figure 11.43
Orange-crowned Warbler.

Figure 11.44
Virginia's Warbler.

g). Relatively common summer resident locally in the White Mountains, between 6,750 and 9,500 ft (2,060 and 2,900 m).

This warbler is most abundant on upper slopes in groves of Mountain Mahogany, but it also occurs sparingly in riparian willows and around clumps of seviceberry in the pinyon zone. The plant growth these birds occupy is often clumped among boulder piles or near rock slides. A secretive species, it perches in the leaves just below the foliage top and can be difficult to find even when it is singing. Nonetheless, a squeak or hissing note will usually bring the bird into view. Then it characteristically flicks its tail while uttering chip notes in alarm. Virginia's Warblers take insect food from twigs and leaves of deciduous brush; thus, their sphere of activity is focused within several feet of the ground. Reference: Johnson (1976).

Yellow Warbler,Dendroica petechia . (Fig. 11.45) Male length 4 1/2 in (11.25 cm), female length 4 1/4 in (10.5 cm); male weight 3/10 oz (9.3 g), female weight 3/10 oz (8.5 g). Uncommon local summer resident in the White Mountains, between 6,750 and 8,200 ft (2,060 and 2,500 m).

This species dwells in the canopy of riparian vegetation, mainly in canyons on the east side of the range. It also breeds at scattered oases in the valleys on each side of the mountains. Yellow Warblers prefer tree willows and cottonwoods but will venture sparingly into aspen at higher elevations. Low willow and alder growth along streams is used for foraging, although much insect food is also taken well up in the foliage of large trees. Nests too are placed in these trees from near the ground to middle heights. Elsewhere this species is heavily parasitized by Brown-headed Cowbirds, and

Figure 11.45
Yellow Warbler.

this activity is suspected to contribute to the uncommonness of the Yellow Warbler in the White Mountains. References: Biermann and Sealy (1982), Griscom and Sprunt (1957).

Yellow-rumped Warbler,Dendroica coronata. (Plate 11.4) Male length 5 in (13 cm), female length 5 in (13 cm); male weight 2/5 oz (12.3 g), female weight 2/5 oz (12.5 g). Common summer resident in the White-Inyo Range, occurring from 8,200 to 10,500 ft (2,499 to 3,200 m).

This species summers in Subalpine Forest of Bristlecone Pine, Limber Pine, or Lodgepole Pine, and in associated riparian trees such as aspen. One of the most generalized foragers of all warblers, it takes insects from the foliage by gleaning and hovering and from the air by flycatching. All levels of the habitat are visited, from the ground to the tops of tall conifers. During the nonbreeding season, berries are often eaten. The Yellow-rumped Warbler also varies its nest sites from near the ground to high in the conifers. Reference: Hubbard (1969).

Black-throated Gray Warbler,Dendroica nigrescens. (Plate 11.2) Male length 4 5/8 in (11.8 cm), female length 4 1/2 in (11.5 cm); male weight 1/4 oz (8.1 g), female weight 3/10 oz (8.9 g). Very common summer resident in the White-Inyo Range, from 6,750 to 9,500 ft (2,060 to 2,900 m).

This warbler's preference for sunny and warm environments is reflected in its increasing abundance from north to south in the woodlands of the White-Inyo mountains. Arid portions of Pinyon-juniper Woodland are favored, with occasional use of Mountain Mahogany. The Black-throated Gray Warbler must occur in huge numbers, as it is one of the most commonly encountered species in the region. Its "see-saw," buzzy song, rising in pitch near the end, is a characteristic sound of the pinyon zone through the spring and summer. Adult Black-throated Grays hunt for insects and spiders in dense terminal needle clusters of pinyon. Nests are built in pinyons or in nearby brush. References: Marshall (1957), Morrison (1982).

MacGillivray's Warbler,Oporornis tolmiei. (Fig. 11.46) Male length 4 4/5 in (12.25 cm), female length 4 3/4 in (12 cm); male weight 3/8 oz (10.8 g), female weight 3/8 oz (10.7 g). Common summer resident in the White Mountains, between 6,750 and 9,500 ft (2,060 and 2,900 m).

This warbler inhabits thick undergrowth along streams, attaining its greatest numbers between 8,200 and 9,000 ft (2,500 and 2,740 m) in willows, alder, Water Birch, nettles, and aspen saplings. Shade and dampness are prominent features of the species' habitat. MacGillivray's Warblers forage for insects and nest near the ground in dense foliage and branchwork; thus, they can be very difficult to observe. When singing, however, males are commonly exposed in bush tops from 5 to 15 ft (1.5 to 4.6 m) above the ground. During migration, this species occurs much more widely and can be found even in very open country near damp spots, as long as there is relatively thick brush nearby with shady hiding places. References: Grinnell and Storer (1924), Hutto (1981).

Figure 11.46
MacGillivray's Warbler.

Figure 11.47
Yellow-breasted Chat.

Yellow-breasted Chat,Icteria virens. (Fig. 11.47) Male length 6 7/8 in (17.5 cm), female length 7 in (17.75 cm); male weight 7/8 oz (24.9 g), female weight 1 oz (27.8 g). Local and rare summer resident in the White Mountains, with records at 6,750 ft (2,060 m), an unusually high elevation for the species.

The Yellow-breasted Chat nests only in the densest riparian thickets in foothill canyons on the east side of the range. Total numbers in the region are probably very small. Lush growth of willows, Wild Rose, nettles, and cottonwood saplings are used for all activities. Because of these habitat preferences, chats are usually very difficult to see in their impenetrable haunts. Their presence is typically revealed by an unusual song, a mixture of harsh and varied rattles interspersed with clear whistles. The singing male is commonly obscured by foliage, but patience will be rewarded by a spectacular song flight occurring between thickets, in which the legs are dangled and wings slowly fluttered. Food consists of insects, spiders, and small fruits. References: Petrides (1938), Thompson (1977).