166 BULLETIN 203, UNITED STATES NATIONAL MUSEUM 



bottom and outside of the nest seemed to be about finished ; one side of 

 it, opposite the most exposed side, was anchored to a nearby twig with 

 strands of plant fiber. Tlie female seemed utterly fearless ; the male 

 was more shy, but his streaked breast was occasionally seen at the nest. 



Robie W. Tufts tells me that he has seen the male at the nest; he 

 saw a male come to a partly finished nest sit in it for over a minute as 

 though testing the workmanship and sing twice while sitting there. 

 The male is always very attentive during nest-building, following his 

 mate back and forth on her trips for material and keeping close to 

 her most of the time. His interest in the nest is so keen that it would 

 be strange if he did not sometimes help. 



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 cinnamonfern 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 2i^ inches in diameter, ex- 

 ternally. 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% to 2 inches in diameter, and from li/4 to li/^ inches in depth. 



None of my nests contain any feathers, but Dr. Roberts (1936) 

 tells of a nest that was made entirely of chicken feathers, with "not 

 a bit of material of any other kind." It was built in a jewel weed 



