Taylor and Shaw (1927) write: “On entering the great forest of the Pacific Northwest, with its solitude, the deep-shaded grandeur of its brown-barked pillars and its stillness, one can almost imagine himself in a different world. Incessantly repeated, apparently from the very crowns of the trees, comes the song of the Townsend warbler, denizen of upper foliage strata. Found in early summer from Alaska south to the State of Washington, the Townsend warbler finds on Mount Rainier approximately the southern limit of its breeding range.” Similar haunts seem to have been chosen wherever the species has been found breeding.
Spring.—The spring migration, apparently directly northward from Mexico, seems to be quite prolonged. Dr. Alexander F. Skutch tells me that the last of the winter visitors do not leave Guatemala until about the first of May. Professor Cooke (1904) says that “an early migrating Townsend warbler was seen on April 9 in the Huachuca Mountains of Arizona. Migrants from Mexico begin to enter southern California April 14 to 20. * * * First arrivals have been reported from Loveland, Colo., May 11, 1889.” And “the average date of the first seen during five years at Columbia Falls, Mont., is May 7.” Mrs. Amelia S. Allen writes to me from Berkeley, Calif., that Townsend’s warbler is an abundant fall and spring migrant in California, where it is also a common winter visitant. “In the spring they begin to increase about the middle of March, when singing flocks go through the live oak trees, feeding on the small oak worms. They become less conspicuous after the middle of April, but if there are rains in the first half of May to delay migrations, occasional flocks are seen. My latest date is May 17, 1915.”
Rathbun, in his Washington notes, writes: “In the spring of 1916, in the Lake Crescent region, a great majority of the individuals came in two distinct waves. The first occurred on April 28 and this lasted for two days, on the second of which the birds were less numerous. After an interval of a day on which we failed to see any of these warblers, there followed a second wave, on May 1, much larger than the one preceding. It consisted of hundreds of these warblers, together with individuals of other species, the main body of which followed the belt of deciduous trees along the shore of the lake. This fact we verified by ascending the adjacent mountain side to a considerable elevation during the movement, where we found but few birds. Descending to the lake level to note the migration, we found the birds close to the ground, the trees being of small size. As most of the Townsend’s warblers were males in high plumage, the sight was most attractive. All were in constant song and flitting about with rapid movements. In their company were many chestnut-backed chickadees, a few Sitka kinglets, many Hammond’s flycatchers, and now and then an Audubon’s warbler and a red-breasted nuthatch. This movement began about half past eight in the morning and lasted until ten o’clock, when the number of birds began to diminish rapidly, and during the remainder of the day was inconsequential.”
On April 25, 1917, he saw a similar flight at the same place. “The day was rather warm and somewhat overcast, and the wave continued intermittently throughout the greater part of the day, the song of Townsend’s warbler being much in evidence most of the time. In this movement the birds passed by in small detached companies at intervals, but the aggregate number was large.”
Nesting.—Not too much is known about the nesting habits of Townsend’s warbler, but enough is known to indicate that nests reported in willows during the last century were evidently wrongly identified. The species is now known to nest only in firs, though possibly it may sometimes be found to select other conifers as nesting sites. Nests and eggs are still very scarce in collections.
The first authentic nests were found by J. H. Bowles (1908) near Lake Chelan, Wash., on June 20, 1908. The two nests, each containing four newly hatched young—
were both placed about twelve feet up in small firs, one some five feet out on a limb, the other close against the main trunk. Both were saddled upon the limb, and not placed in a fork nor in a crotch.
The construction of both nests was identical, and entirely different from any of the descriptions that I have read. They were firmly built, rather bulky, and decidedly shallow for the nest of a warbler. The material used appeared to be mostly cedar bark, with a few slender fir twigs interwoven. Externally they were patched with a silvery flax-like plant fiber, while the lining seemed to be entirely of the stems of moss flowers. To an eastern collector it resembled an unusually bulky and considerably flattened nest of the Black-throated Green Warbler, lacking any sign of feathers, however, in its construction.
A nest with five eggs is in the Thayer collection in Cambridge, taken by C. deB. Green on Graham Island, British Columbia, June 24, 1912. It is described as placed “on top of the big limb of spruce tree,” and is large, compact, and well-built, being made largely of fine plant fibers, mixed with strips of grasses, mosses, lichens, fine strips of inner bark, plant down, and a few spider cocoons—all firmly woven together and neatly and smoothly lined with long, fine, white hairs and one feather. It measures externally 21⁄4 inches in height and 3 by 31⁄2 in diameter; the cup is 11⁄2 inches deep and about 2 inches in diameter.
A set in my collection now in the U.S. National Museum was taken by F. R. Decker in Chelan County, Wash., on June 23, 1923; the nest was about 15 feet up and 8 feet out on a limb of a fir tree and contained five fresh eggs. Both birds remained close while the nest was being taken. Two nests in the Doe Museum, at Gainesville, Fla., were taken by J. H. Bowles in Washington, 9 and 10 feet up in small, slender firs, June 2 and 4.