Influence of Rocky Shore Characteristics on the Foraging Profitability of Eurasian Oystercatchers Haematopus ostralegus

Abstract

Habitat characteristics and microhabitat of organisms pose a number of choices to foraging species, for example where and how to search for prey, which prey to select and what foraging technique to employ. Predators can enhance the profitability of foraging by adapting their strategies flexibly in relation to prey characteristics and environmental factors. To investigate the influence of rocky shore characteristics viz., condition of rock, position of limpet on the rock, stage of tide, and limpet opening technique of oystercatcher on the profitability of limpet foraging, a total of 193 attacks on limpets (Patella spp.) by Eurasian oystercatchers (Haematopus ostralegus) were made on Lundy Island, UK, using focal animal sampling. Multiple regression revealed that profitability was influenced by the condition of the rock and the limpet opening technique employed by oystercatchers. The profitability of the limpet opening technique appears to be associated with the condition of the rock. Oystercatchers forage by adapting their foraging strategy in accordance with the nature of the rocks i.e. wetness on which they are foraging.