A MODEL TO EXPLAIN MOLT-BREEDING OVERLAP AND CLUTCH SIZE IN SOME TROPICAL BIRDS.

摘要: The tendency for avian clutch size to decrease with latitude is well documented (Lack, 1947, 1948; Lack and Moreau, 1965; 1944; Skutch, 1949, 1967a). Most of the hypotheses proposed explain this phenomenon suggest that energy (either food itself or time used gather it) in some way limiting. (1947, 1948, 1966) indicates mean represents largest number young which parents can find adequate food. Because shorter days 1947) heavy rains (Foster, 1974a) daylight hours available feeding, tropical birds presumably feed fewer than temperate forms. Ricklefs (1970) postulates increased intersp,ecific competition among as compared predators causes a reduction abundance (insects) thus results low productivity predators, i.e., birds. Cody (1966) suggests must devote proportionally mo,re improving predator avoidance competitive ability do forms, even at expense reproduction, because both predation are higher tropics. In view above, large species New World African tropics molt while breeding interest. Although most investigators have considered molt-breeding overlap only incidental other studies, has now been reported 1974b) 122 (excluding all Australian arid region birds). Molt, usually temporally independent an energetically demanding process. Thus form something paradox. These appear additional during period could be devoted reproduction but not. Organisms not utilize potentially process should selective disadvantage. purpose present paper define set circumstances channelling into molt, breeding, may selectively advantageous.