Behavior.—Virginia’s warbler is a shy, retiring species, spending most of its time not far above the ground in the thick underbrush, where it is not easily seen, as its colors match its surroundings. It is also very lively and active, almost constantly in motion, except when it mounts to the top of some dead bush or small tree to sit and sing.
Voice.—Dr. Chapman (1907) quotes C. E. Aiken as follows: “The male is very musical during the nesting season, uttering his swee ditty continually as he skips through the bushes in search of his morning repast; or having satisfied his appetite, he mounts to the top of some tree in the neighborhood of his nest, and repeats at regular intervals a song of remarkable fullness for a bird of such minute proportions.” Henry D. Minot (1880) calls the "ordinary note, a sharp chip; song, simple but various (deceptively so); common forms are ché-we-ché-we-ché-we-ché-we, wit-a-wiť-wiť-wiť (these terminal notes being partially characteristic of Helminthophagae) and che-wé-che-wé-che-wé, ché-a-ché-a-ché". Dr. Linsdale’s (1938) comments on singing males follow:
The song varied from 7 to 10 notes, being usually 8, and it occupied about 3 seconds. At the beginning the notes were slow and they came more rapidly at the end. About half a minute elapsed between songs. Another bird sang 14 times in 3 minutes and 10 seconds. * * * Singing perches on dead limbs that were rather exposed were the rule, but they were not often as high as the tops of tall trees. * * * On June 16, 1930, near Kingston Creek, 7500 feet, a singing male was followed for an hour, beginning at 7:30 a. m. It sang about every 30 seconds. The territory over which it moved was surprisingly large, estimated as extending 400 yards along the cañon slope and vertically about 150 yards, from near the stream to the base of the broken cliffs. * * * The song, compared with that of the Tolmie warbler had a more rapid rhythm and the notes were thinner and weaker. It could be distinguished from that of the Audubon warbler by the lack of rising inflection at the end. The song was represented by the observer (Miller) as zdl-zdl-zdl-zdl, zt-zt-zt-zt.
Field marks.—Virginia’s warbler, with its plain gray upper parts, is an inconspicuous bird, and its shy, retiring habits make it difficult to observe. The chestnut crown patch is not prominent and is often invisible. The yellow on the chest and throat of the male is quite variable and in the female and young much reduced or lacking. The best field marks are the dull yellow rump and upper and under tail covers, which are more or less conspicuous in old and young birds at all seasons.
Enemies.—O. W. Howard (1899) says that “the nests of the bird, like those of other ground-nesting birds of this locality, are destroyed by jays and snakes. The jays steal both eggs and young. Often a whole band of these winged wolves will sweep down on a nest and in less time than it takes to tell it they will devour the contents and destroy the nest, the pitiful notes of the helpless parents being drowned by the harsh notes of the marauders.”
Frank C. Cross writes to me that Robert J. Niedrach showed him a nest of this warbler that contained a young cowbird and one young warbler.
Winter.—By the last of August or early September, Virginia’s warblers have retired from their northern breeding haunts, to spend the winter in southern Mexico. Dr. C. William Beebe (1905) writes: “Occasionally in the mornings, numbers of tiny grayish warblers came slowly down the walls of the barranca, feeding as they descended, taking short flights, and keeping close to ground among the dense underbrush. These birds lingered at the camp for a time, and then, with soft, low chirps, all passed on to the water, where they alighted on the sand and drank. Then, as if at some silent signal, all flew up and returned quickly, still keeping close to the ground, zig-zagging their way upward in a long line, like tiny gray mice.” These were, of course, Virginia’s warblers.
DISTRIBUTION
Range.—Western United States to Southern Mexico.
Breeding range.—Virginia’s warbler breeds north to central eastern California (White Mountains); central and northeastern Nevada (Kingston Creek, Ruby Mountains, and East Humboldt Mountains); northern Utah (Salt Lake City, Parley’s Park, Packs Canyon, and Ashley); possibly southeastern Idaho (Joe’s Gap, Bear Lake County; one specimen from Bancroft, Bannock County); and northern Colorado (probably Little Snake River, Moffat County, and Estes Park). East to the eastern slope of the Rocky Mountains in Colorado (Estes Park, Denver, Manitou, Fountain, and Beulah); in migration has occurred east to Limon, and Monon in Baca County close to the Kansas line; and central New Mexico (Tierra Amarilla, Lake Burford, Sandia Mountain, and Apache, probably). South to southwestern New Mexico (Apache); and southeastern Arizona (Paradise and the Huachuca Mountains). West to southeastern and central Arizona (Huachuca Mountains, Santa Catalina Mountains, and Prescott); and eastern California (Clark Mountain and White Mountains; casually in migration to Lemon Grove).