The Night Jars, or Fern Owls, as they are sometimes called, are found throughout all divisions of our globe, with the exception of its most northern latitudes; two species are met with in Europe, and others occur in America, Africa, and Asia. Though thus spread over the face of the earth, the actual habitat of this group is somewhat limited; certain amongst them occupy mountains, others frequent desert tracts or fruitful plains, but all keep to a certain extent within the limits of their appointed domain, their plumage being usually coloured so as to harmonise and blend with the tints of the rocks, sand, or tree trunks, among which they pass the greatest portion of their lives. Such of these birds as dwell in tropical forests do not migrate; and the greater number skim over the surrounding country at certain seasons; but all those inhabiting northern latitudes withdraw in the autumn towards the south. It is only during these migratory excursions--which often extend as far as the interior of Africa--that the Night Jars exhibit anything like a social disposition; in their native haunts each pair keeps entirely apart from others, and never allows the slightest intrusion within the precincts of the locality selected for its abode. It may occasionally happen that some tempting neighbourhood will induce several couples to settle comparatively near together, but under any circumstances the same utter want of intercourse among them is observable. Towards man they by no means exhibit this want of sociability, and in most parts of the earth more or less frequent the immediate vicinity of his dwellings. Almost all these birds seek for insects--upon which they principally subsist--during the night, and retire to sleep within their favourite recesses as soon as morning dawns; but some American species are an exception to this rule, as they fly about in quest of prey not only in the daylight, but even when exposed to the full glare of the sun. Upon the ground they may be said to recline, rather than to perch or sit, and their gait, when attempting to take a few steps over its surface, is remarkably clumsy; their powers of flight, however, make ample amends for this deficiency, combining the facility and swiftness with which we are familiar in the movements of the Falcon and the Swallow.