The nest, when finished, is a symphony of pale buff and silvery grays that shade imperceptibly toward the buff touches on the under parts of the warbler and are lighted as with a gleam of sunlight by the bright yellow of the remaining plumage. Yet this bright yellow has a greenish tint that is deepened in the tender green of the young shoots of the barberry, while the yellow itself is again reproduced in the blossoms. No wonder this lovely little singing-bird loves a barberry bush for its nest. It finds protection and an artistically satisfying color scheme in the same bush. The silvery grays of the nest are the fine, silky, fibrous inner bark of the milkweed, whose last year’s stems are shredded by wind and storm in time for the nest-building. These barberry-bush-building yellow warblers with whom I have been more or less acquainted for a quarter of a century seem to care for little else for material, though sometimes they make the fern fuzz more adhesive with caterpillars’ silk and line with a few horsehairs and soft feathers. Yet though these nests have been invariable in material they have varied otherwise. Some have been so firmly woven and the material so stoutly packed as to defy the storms of a winter or two. Others have been so frail as hardly to be found when the leaves are off. Perhaps these slight nests are made by birds that were nestlings of the previous year and have not yet learned the complete art of nest-building. Once I found one whose makers were skilled indeed. Instead of placing it firmly in a crotch and building up with the fern wool within a netting of fiber wound from twig to twig, as is the usual method, these had launched boldly into a new architecture. Perhaps they had neighbored the year before with a vireo. Anyway, they took the vireo’s plans and built a yellow warbler’s nest on them, hanging it from a nearly horizontal barberry fork, and finishing a fine, firm, pensile nest, vireo style, out of yellow warbler material. I never found this nest’s successor, and I am not sure whether, having found they could do it, they abandoned the type for the old home style, or whether something happened to the birds, and thus the warbler world lost budding genius. Only one other nest have I found that seemed to be in any way abnormal, and this, unlike the pensile nest, seems to have had a very definite reason for its abnormality. The hollow part which had contained the eggs and young was in no wise different from that of all other warblers’ nests. It was the depth and firmness of the foundation which surprised me. This was built up to the height of an ordinary yellow warbler’s nest before the real nest began at all, and (the young had flown) I promptly took it home and dissected it.