Young people readers will perhaps recall my previous reference to the whims and preferences of the birds in their selection of building material. The unravelling of deserted nests will often prove an instructive as well as humorously entertaining pastime, revealing in the same fabric evidences of great sagacity and what would appear perfectly nonsensical prejudices, with an occasional piece of positive frivolity. Thus we can readily see the wisdom in the selection of these strong strips of milkweed bark with which this vireo's or yellow-warbler's nest is moored to the forked branch, or the strands of twine with which the Baltimore oriole suspends its deep swinging hammock, as well as the plentiful meshing of horse-hair woven through the body of the nest. The nest of the orchard oriole is even more remarkable as a piece of woven texture. Wilson, the ornithologist, by careful unravelling of a grass strand from one of these nests, found it to have been passed through the fabric and returned thirty-four times, the strand itself being only thirteen inches long, a fact which prompted an old lady friend of his to ask "whether it would be possible to teach the birds to darn stockings." The horse-hair in the nest of the hang-bird gives it a wonderful compact strength, capable of sustaining a hundred times the weight of the bird. Upon unravelling one, I found it intermeshed fourteen times in the length of ten inches, which would probably have given a total number of forty passes in the full length of the hair. No one will question the sagacity which such materials imply; but what is to be said of a bird that selects caterpillar-skins as a conspicuous adornment for her domicile? And here is a vireo's nest with a part of a toad-skin prominently displayed on its exterior, or perhaps a specimen such as I have previously described abundantly covered with snake-skins. These, of course, are whims pure and simple. In the linings of many nests we find an equal variety, but the materials are selected with a definite purpose, a soft, warm bed for the young fledglings being the object sought by the parent birds. To this end we find many nests lined with what the ornithologists call "soft downy substances." Examination with a magnifying glass will sometimes show us precisely the nature of this down; whether it consists of wool from a sheep or hair from the deer, 'coon, goat, or horse; whether it is composed of fuzz from downy leaves or spider-webs, caterpillar hairs, or cottony seeds of plants. These last form a favorite nest lining with a number of birds.