LAYING PLASTICITY IN AN AVIAN BROOD PARASITE

Females of some bird species “steal“ the parental care of other breeding individuals by laying eggs parasitically in their nests. In most populations, conspecific brood parasites lay parasitically before laying in their own nests. By contrast, in a young and expanding Common Moorhen (Gallinula chloropus) population, 17.4% (n = 8) of brood parasites laid parasitically when their own clutches were currently being incubated, and 13.1% (n = 6) laid parasitically when they were tending to their young. This result differs from previous data on conspecific brood parasitism in this (and other) avian species and suggests that sitespecific ecological conditions exert differing selective influences on the behavioral development of populations. The behavior adopted by individual vertebrate species may not, therefore, be rigidly fixed throughout their geographic range.