KLEPTOPARASITISM IN BIRDS

Kleptoparasitism refers to the interspecific stealing of already procured food, but this paper shows that intraspecific food-stealing is effectively the same behaviour. A comprehensive review of the literature shows that certain orders of birds contain a disproportionate number of kleptoparasitic species. Birds in these orders occupy a limited range of ecological niches and are most commonly either predatory or dietary opportunists. Kleptoparasitism is particularly associated with certain ecological conditions, such as the availability of hosts feeding on large, visible food items and periods of food shortage. Birds show a wide range of socially parasitic feeding interactions of which kleptoparasitism is one extreme. The parasitic pattern of food-stealing is likely to involve frequency-dependent selection and may be an example of an evolutionarily stable strategy. © 1979.