like all other nests, save those of birds of prey, clean and pure, when the young are flown. This they do chiefly from an instinct of delicacy; since wood-birds are not wont to use the same nest a second time, even if they rear several broods in a season. The subdued tints and notes which almost always mark the female sex, among birds,--unlike insects and human beings, of which the female is often more showy than the male,--seem designed to secure their safety while sitting on the nest, while the brighter colors and louder song of the male enable his domestic circle to detect his whereabouts more easily. It is commonly noticed, in the same way, that ground-birds have more neutral tints than those which build out of reach. With the aid of these advantages, it is astonishing how well these roving creatures keep their secrets, and what sharp eyes are needed to spy out their habitations,--while it always seems as if the empty last-year's nests were very plenty. Some, indeed, are very elaborately concealed, as of the Golden-Crowned Thrush, called, for this reason, the Oven-Bird,--the Meadow-Lark, with its burrowed gallery among the grass,--and the Kingfisher, which mines four feet into the earth. But most of the rarer nests would hardly be discovered, only that the maternal instinct seems sometimes so overloaded by Nature as to defeat itself, and the bird flies and chirps in agony, when she might pass unnoticed by keeping still. The most marked exception which I have noticed is the Red Thrush, which, in this respect, as in others, has the most high-bred manners among all our birds: both male and female sometimes flit in perfect silence through the bushes, and show solicitude only in a sob which is scarcely audible.