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 jewelweed (_Impatiens capensis_), but after a brisk wind and a sharp shower both nest and weed were completely wrecked. He shows a photograph of a nest built almost entirely of sheep wool, and speaks also of the use of fine strips of inner tree bark, which probably occur in many nests, of quantities of fine, white, silky pappus from various plants, and of a few feathers. Du Bois mentions in his notes a nest in which five soft, white chicken feathers were woven into the lining, the largest one when stretched out measuring 3-3/4 inches; there were also two or three feathers in the body of the nest. In my collection is a beautifully camouflaged nest that was built in the upright crotch of a small poplar and seems to be made very largely of white cotton mixed with fine, light-colored fibers. It is lined with cotton, and with a few green poplar leaves fastened to the exterior, the whole being firmly bound with some of the finest fibers and with spider silk, the light-colored material matches the bark of the tree so closely that it might easily be overlooked. T. E. McMullen has sent me his data for over 40 nests of the eastern yellow warbler found in New Jersey and Pennsylvania. The lowest nest was only 1 foot from the ground in a small bush, and the highest was 30 feet up in an elm. In addition to the shrubs and trees mentioned above he lists arrowroot, blackberry briers, elder, holly, Osage-orange and button-bushes, birch, wild cherry and oak saplings, and a pear tree. The well-known habit of building nests one or more stories over cowbirds' eggs will be discussed under the enemies of the yellow warbler.