In the nesting habits the diversity is greatest. Some ground species excavate in the earth like kingfishers, only with greater skill, making cylindrical burrows often four to five feet deep, and terminating in a round chamber. Others build a massive oven-shaped structure of clay on a branch or other elevated site. Many of those that creep on trees nest in holes in the wood. The marsh-frequenting kinds attach spherical or oval domed nests to the reeds; and in some cases woven grass and clay are so ingeniously combined that the structure, while light as a basket, is perfectly impervious to the wet and practically indestructible. The most curious nests, however, are the large stick structures on trees and bushes, in the building and repairing of which the birds are in many cases employed more or less constantly all the year round. These stick nests vary greatly in form, size, and in other respects. Some have a spiral passage-way leading from the entrance to the nest cavity, and the cavity is in many cases only large enough to accommodate the bird; but in the gigantic structure of Homorus gutturalis it is so large that, if the upper half of the nest or dome were removed, a condor could comfortably hatch her eggs and rear her young in it. This nest is spherical. The allied Homorus lophotis builds a nest equally large, but with a small cavity for the eggs inside, and outwardly resembling a gigantic powder-flask, lying horizontally among the lower branches of a spreading tree. Pracellodomtis sibila-trix, a bird in size like the English house sparrow, also makes a huge nest, and places it on the twigs at the terminal end of a horizontal branch from twelve to fifteen feet above the ground; but when finished, the weight of the structure bears down the branch-end to within one or two feet of the surface. Mr. Barrows, who describes this nest, says: "When other branches of the same tree are similarly loaded, and other trees close at hand bear the same kind of fruit, the result is very picturesque." Synallaxis phryganophila makes a stick nest about a foot in depth, and from the top a tubular passage, formed of slender twigs interlaced, runs down the entire length of the nest, like a rain-pipe on the wall of a house, and then becoming external slopes upward, ending at a distance of two to three feet from the nest. Throughout South America there are several varieties of these fruit-and-stem or watering-pot shaped nests; they are not, however, all built by birds of one genus, while in the genus Synallaxis many species have no tubular passageways attached to their nests. One species--erythro thorax--in Yucatan, makes so large a nest of sticks, that the natives do not believe that so small a bird can be the builder. They say that when the _tzapatan_ begins to sing, all the birds in the forest repair to it, each one carrying a stick to add to the structure; only one, a tyrant-bird, brings two sticks, one for itself and one for the