The WARBLERS (_Monticolæ_) constitute a numerous family, whose members vary considerably in size, but closely resemble each other, both in appearance and habits. These birds are recognisable by their slender bodies, moderate-sized or long wings, in which the third quill generally exceeds the rest in length; short tail, either straight or excised at its tip; slender tarsi, and awl-shaped beak, with quite straight or slightly arched upper mandible, the latter furnished with a very short, delicate hook at its extremity. The coloration of their thick, lax plumage differs according to the age and sex, the males being usually much more beautifully coloured than their mates, and the young distinguishable from the adults by the spots with which they are adorned. Many species are remarkable for the brownish red and white hues that predominate in the tail-feathers. Most of the various members of this family occupy rocky or stony districts, whilst some few, on the contrary, frequent woods, gardens, or pasture-land. In disposition they are watchful, lively, and restless, but by no means social, never congregating, even during the migratory season, in flocks, but living invariably in pairs, or at most in families. Morning has no sooner dawned than they commence hopping, or rather running over the ground, climbing among the branches of bushes, or flying about in short courses over a considerable tract of country, always returning to pass the night upon their usual resting-place. Unlike other singing birds, when excited, they bow the head repeatedly, and either flourish and spread their tails or agitate them with a tremulous kind of motion. The voices of this family, though possessing many sweet notes, are generally marred by an intermixture of harsh tones, and a constant repetition of the same cadence. Many species have great facility for imitation, and constantly introduce the notes and strophes of other birds into their own natural song. All such as inhabit the northern portions of the globe migrate to warmer latitudes at the approach of winter, whilst those that live in southern regions remain throughout the entire year in their native lands. The reason of this difference in their habits is at once explained, if we reflect that the insects upon which they almost exclusively subsist are only found in northern countries during the summer, but are readily obtained in southern climes throughout the entire year. Both sexes assist in the labours attendant on building and incubation. The nest, which is carefully hidden from view, is usually situated in clefts or fissures of rocks and stones, or occasionally in hollow trees and similar situations, and though very rudely constructed externally, is provided with a well-lined interior, for the reception of the little family. The eggs, from four to six in number, are generally of a pale blue colour. * * * * *