Mrs. Bailey (1902) says that “its song is a simple warbler lay, zee-ee-zee-ee, ze, ze, ze, with the quiet woodsy quality of virens and caerulescens, so soothing to the ear.” Bowles (1902) heard an unusual song that “was on the principle of a yellow-throated vireo or a scarlet tanager; but the quality of a blue-headed vireo in addition, making a very strong and rich song.”
Field marks.—The gray back, white breast with a few black streaks, two white wing bars, and, particularly, the conspicuous black and white pattern of the head and throat will make this warbler almost unmistakable. The tiny yellow spot in front of the eye is visible only at close quarters. Young birds and adults in the fall show the same characters more or less obscured by brownish edgings. The female has a white throat instead of a black one.
Enemies.—Jays of different species and crows evidently take heavy toll of the eggs and young, as they are persistent nest hunters and often have their own broods to feed near by. Bowles (1902) says that “one pair of California jays seemed to have located every nest that was built in a gulch where they were building their own nest.” One of the Grinnell and Storer (1924) party "interrupted an attack by a California Striped Racer upon a brood of Black-throated Gray Warblers. The female parent was much excited, flying from twig to twig, calling, and fluttering her wings. Near by, on the ground, was one of the young warblers. There was good evidence that the snake had already swallowed another member of the brood.” This warbler seems to have escaped any interference by cowbirds.
Fall.—The southward migration begins in September and is mainly accomplished during that month; Washington is generally vacated during September, but migration continues through California during the first half of October; after the middle of October even southern California is deserted, and the black-throated gray warblers have gone to their winter haunts in Mexico.
DISTRIBUTION
Range.—Western North America from central British Columbia to southern Mexico.
Breeding range.—The black-throated gray warbler breeds north to southwestern British Columbia (Hagensborg and Lillooet). East to southwestern British Columbia (Lillooet and Chilliwack); western Washington (Bellingham and Leavenworth); central northern Oregon (The Dalles); possibly southwestern Idaho (Riddle); southwestern Wyoming, possibly (Mountain); western and southern Colorado (probably Escalante Hills, Coventry, and the Culebra Range); central New Mexico (Santa Fe); and northeastern Sonora (San Luis Mountains). South to northeastern Sonora (San Luis Mountains); southeastern to north-central Arizona (Huachuca Mountains, Santa Rita Mountains, Santa Catalina Mountains, and Bill Williams Mountain); and northeastern Baja California (Sierra San Pedro Mártir). West to northern Baja California (Sierra San Pedro Mártir); western California (San Jacinto Mountains, Glendora, Santa Lucia Peak, and Lakeport); western Oregon (Kirby, Coos Bay, Corvallis, and Portland); western Washington (Spirit Lake and Shelton); and southwestern British Columbia (Victoria, Stuart Island, and Hagensborg).
Winter range.—The principal winter home of the black-throated gray warbler is in western Mexico. It is found in winter north to extreme southern Arizona (Yuma, occasionally in the Baboquivari Mountains, and Tucson). East to southeastern Arizona (Tucson); eastern Sonora (Tesia and Alamos); southwestern Durango (Chacala); northern Michoacán (Patambán); Mexico (city of Mexico); and central Oaxaca (Oaxaca). South to central Oaxaca. West to western Oaxaca (La Parada); Guerrero (Chilpancingo); western Michoacán (Los Reyes); southern Sinaloa (Escuinapa and Mazatlán); southern Baja California (Victoria Mountains and San José del Rancho); and southwestern Arizona (Yuma). It has also been found at this season casually, south to Dueñas, Guatemala, and north to Pasadena and Eureka, Calif., and Cameron County, Tex.
Migration.—Early dates of spring arrival are: New Mexico—Cooney, April 6. Arizona—Santa Rita Mountains, March 21. California—Grass Valley, March 24. Oregon—Portland, April 14. Washington—Tacoma, April 10. British Columbia—Chilliwack, April 16.
Late dates of fall departure are: British Columbia—Courtenay, September 7. Washington—Yakima, October 27. Oregon—Eugene, October 11. California—Diablo, November 11. Arizona—Phoenix, November 8.