At Mount Graham, Ariz., in September, this warbler was found in considerable numbers, though the few taken were procured with no little difficulty, for they almost invariably were seen in the tops of the tallest trees, where a glimpse might now and then be had of them as they dashed out after flying insects, or flew from tree to tree in their always onward migratory course. The tracts of pine woods they shunned entirely, but affected the firs and spruces, and their flights from point to point were regulated and made longer and shorter by the presence or absence of these trees. Their movements were exceedingly rapid; a moment spent in passing in and out the interlacing branches, a few hurried sweeps at their extremities, and they were off to the next adjoining tree to repeat the process again and again till lost sight of in the dense woods.
Winter.—A few straggling Townsend’s warblers spend the winter occasionally as far north as Oregon and Washington; the species is fairly common from central California southward; but the main body of the species retires to Mexico and Central America. Mrs. Allen tells me that they are quite abundant in the redwood trees of California in winter; and in midwinter, she has “many records of their coming under the eaves of the house, where they seem to be taking spiders.”
Dr. Skutch has contributed the following account: “Townsend’s warblers winter in vast numbers in the highlands of Guatemala. From their arrival in September until shortly before the departure of the last in May, I considered these the most abundant of all birds, whether resident or migratory, between 7,000 and 10,000 feet above sea-level on the Sierra de Tecpán in west-central Guatemala. Here they were almost equally numerous in the forest of pine, oak, alder and arbutus and in the nearly pure stands of lofty cypress trees (Cupressus benthamii) on the mountain-top. But they are widespread over the Guatemalan altos, from 5,000 to 10,000 feet above sea-level, and even pass the winter at considerably lower altitudes, where pine woods locally replace the broad-leafed forest prevalent in these less elevated regions. Thus on the Finca Mocá, a huge coffee plantation lying on the southern side of the Volcán Atitlán, a local stand of pine reaches to about 3,000 feet above sea-level. Among these pines I found Townsend’s warblers wintering down to at least 3,400 feet, in company with such birds as hermit warblers and Coues’ flycatchers—all of them highland species which I failed to find at so low an altitude in the neighboring dicotyledonous woods more typical of the region.
“By the time the Townsend’s warblers began to arrive from the North, the great majority of the resident birds of the Sierra de Tecpán had finished breeding for the year, and those of sociable habits had begun to flock. The pretty Hartlaub’s warblers (Vermivora superciliosa) formed the nuclei of the mixed companies of small birds which roamed through the rain-drenched woods at the beginning of September. The newly arrived Townsend’s warblers at once joined these flocks, falling in with the resident birds as though they had never been absent in far northern lands. Soon they outnumbered all other birds in these motley parties. They were monotonously abundant; and despite their beauty, I was more than once exasperated, when I had striven until my neck ached to obtain an adequate glimpse of some small, elusive bird flitting through the high treetops, to find at last that it was just one more Townsend’s warbler. There was always another of the same kind much lower among the branches, which I might have admired with less flexure of the neck! At 5,000 feet and below, the plainly attired Tennessee warbler replaces the elegant Townsend’s warbler as the most abundant member of the mixed flocks.
“By the middle of April, the Townsend’s warblers on the Sierra de Tecpán began to sing—a dreamy, lazy sort of song, which reminded me much of that of the black-throated green warbler. Through the remainder of the month, I repeatedly heard this simple song, sounding always as though it came from far away. Soon the ranks of the Townsend’s warblers began to thin; and after May 2 I saw them no more. Males were present as late as April 28; but the last that I saw, on May 2, was a female. The withdrawal of the countless black-and-yellow warblers, together with that of the other migratory species that flocked with them, left a void among the treetops, which was not filled until their return just 4 months later.
“Early dates of fall arrival in Guatemala are: Guatemala City (Anthony), September 7; Sierra de Tecpán, September 2, 1933; Huehuetenango, September 11, 1934. Late dates of spring departure from Guatemala are: Guatemala City (Anthony), May 1; Sierra de Tecpán, May 2, 1933.”
Dickey and van Rossem (1938) say that “Townsend’s warbler is a decidedly uncommon species in El Salvador, which probably marks about the southern limit of the winter range. The winter distribution, locally, is practically confined to the oaks and pines of the interior mountains where conditions most closely parallel those prevailing in the breeding range.”
DISTRIBUTION
Range.—Western North America.