The eastern yellow warbler builds a neat, strong nest, the materials being firmly and smoothly interwoven and the lining compactly felted. Five local nests before me show quite a variation in the materials used and in their arrangement. The most obvious material, occurring more or less in all of the nests, consists of the silvery-gray strands from the last-year's stalks of milkweed, Indian hemp, or other similar dead weeds. One nest has a great mass of such material below it on one side, evidently to fill in space in the fork that supported it; mixed with this material are a few strands of grasses, other shredded weed stems, bits of wool, and gray fur. Although this nest is far from neat externally, the cup of the nest is well and firmly made of finer silvery fibers and fine grasses, cinnamon-fern down, with which it is profusely lined, and a few fine white hairs. The rim is strongly reinforced with horsehair and decorated with the cinnamon down. This nest, the largest of the lot, measures nearly 5 inches in height and 3 inches in diameter, externally. The smallest and the neatest of the five is made of finer strands of similar materials, without a trace of cinnamon-fern down, the whole being very firmly and smoothly woven into a compact little nest; the rim is neatly made of very fine grasses, and it is smoothly lined with white plant-down; it measures only 2 inches in height and 2-1/4 inches in diameter, externally. Grasses enter largely into the construction of all the nests. One in particular is lined with both white and buff plant-down and a little very fine grass, and has a solidly built rim of strong grasses very firmly interwoven; the foundation consists of dry brown and gray lichens, or mosses, and a lot of cotton waste, such as is used to clean machinery. A two-story nest, which measures 4 inches in total height, is profusely lined with white cotton in both stories. There is little difference in the internal measurements, which vary from 1-3/4 to 2 inches in diameter, and from 1-1/4 to 1-1/2 inches in depth.