Review of inter and intraspecific predation by shorebirds

Abstract

Predation is often the most important driver of breeding productivity and population dynamics in birds, with an increasing impact in the currently rapidly changing world. Despite decades of intensive research, our understanding of trophic interactions and food webs is still limited. Although there is good knowledge of regular predators within particular groups of animals, focused overviews of such predator-prey interactions are often lacking. Here, I review predation behaviour by shorebirds: plovers, sandpipers and allies, over the globe - presenting 16 cases of interspecific predation relationships and two cases of intraspecific predation of eggs or chicks, altogether involving 11 species of predators and 13 species of prey. Predator species are usually bigger and more aggressive than prey species. Contrary to the usually anecdotal nature of predation interactions among shore-birds, Ruddy Turnstone (Arenaria interpres) and Bristle-thighed Curlew (Numenius tahitiesis) can represent a significant threat for other breeding birds in coastal habitats, r where high egg depredation rates can be detrimental, causing complete reproduction failure in colonies of gulls and terns. Apart from pointed bill of both species, Bristle-thighed Curlew, uniquely among shorebirds, can use stones for egg opening. Furthermore, turn-stones are not perceived as potential predators in gull colonies which render them successful egg predators. This review (i) suggests that even shorebirds, generally perceived as consumers of invertebrate prey, can become vigorous predators of vertebrates including their own kind; (ii) highlights that such behaviour might be overlooked and more common than previously supposed, possibly present in other groups of birds too, extending our knowledge on food web complexity.