THE NEST AS A DORMITORY

摘要: Summary As a rule, only birds which breed in roofed nests or those built enclosed spaces sleep their when not incubating brooding young. The chief exceptions are rails, coots, and gallinulse, build platforms to raise them above the water wet ground while they sleep, Curved-billed Thrashers, roost on open thorny cacti. The first step evolution of dormitory habit appears be sleeping covered breeding nest itself before eggs laid after fledglings depart. In simplest case, one parent occupies nest. But number species, second uses as even it contains nestlings, sometimes unmated helpers with parents. A further advance is made led have just left. The next construction special dormitories, intended for eggs. These usually resemble nest, but differences form site found, especially tropical wrens. Only make acquire addition nests, likely enjoy such lodges through year. them, self-supporting individuals may singly, pairs, dependent offspring. final stage habit, young lodge parents long self-supporting. Often each family remains separate throughout year; sometimes, probably consequence loss several families club together non-breeding season. Numerous examples foregoing arrangements given. In harsh environment, at high latitudes timberline mountains, many seek closed sleeping, lives depend availability protection. Nevertheless, best developed mild climates where permanently resident.