Many of the birds which find their food at sea, or in the waters of stream and lake, repair to the trees for the purpose of building their nests among the branches. Such birds are the pelicans, herons, ibises, and ospreys; while the wood ducks lay their eggs high above the ground in the hollows of trees. Parrots, kingfishers, swifts, and hummingbirds are almost helpless on the ground, their feet being adapted for climbing about the branches, perching on twigs, or clinging to the hollows of trees. Taken as a whole, birds would suffer more than any other class of creatures in a deforested world. The woodpeckers would be without home, food, and resting-place; except, possibly, the flicker, or high-hole, who is either a retrograde or a genius, whichever we may choose to consider him, and could live well enough upon ground ants. But as to his nest--he would have to sharpen his wits still more to solve successfully the question of the woodpecker motto, "What is home without a hollow tree?" Great gaps would be made in the ranks of the furry creatures--the mammals. Opossums and raccoons would find themselves in an embarrassing position, and as for the sloths, which never descend to earth, depending for protection on their resemblance to leaves and mossy bark, they would be wiped out with one fell swoop. The arboreal squirrels might learn to burrow, as so many of their near relations have done, but their muscles would become cramped from inactivity and their eyes would often strain upward for a glimpse of the beloved branches. The bats might take to caves and the vampires to outhouses and dark crevices in the rocks, but most of the monkeys and apes would soon become extinct, while a chimpanzee or orang-utan would become a cripple, swinging ever painfully along between the knuckles of crutch-like forearms, searching, searching forever for the trees which gave him his form and structure, and without which his life and that of his race must abruptly end.