Effects of Nesting Gray-headed Lapwings Microsarcops cinereus on the Intensity of the Artificial Nest Predation by Carrion Crows Corvus corone

Abstract

This study investigated the effects of nesting Gray-headed Lapwings Microsarcops cinereus on the intensity of the predation by Carrion Crows Corvus corone on eggs in artificial nests at the Nabeta reclaimed land in 1990 and 1991. The survival rate of the eggs in artificial nests increased during the Gray-headed Lapwings' breeding season because of their nestdefense behavior. Among the artificial nests placed in their territory the number of survivors for 24 hours was larger during the incubating and fledging period than during the territory-making period. The number of Carrion Crows that intruded in the defendedd area during the breeding season of Gray-headed Lapwings was significantly smaller than that during the pre-breeding period. These findings suggest that the nestdefense behavior of Gray-headed Lapwings inhibits the opportunities of nest predation by Carrion Crows.