Limpet Patella spp. consumption by oystercatchers Haematopus ostralegus:a preference for solitary prey items

Abstract

Patellid limpets are very important grazers on NE Atlantic rocky shores, and can occur in clumps or as solitary individuals. When oystercatchers are foraging for Limpets on rocky shores, they are often presented with a choice between solitary and clumped h p e t s . We attempted to establish whether oystercatchers express a preference for limpet prey ltems from these different distributions. Oystercatchers spent far more time foraging in areas of less clumped limpets than in areas of clumped limpets, despite lower prey density. We found a strong preference for sohtary prey items, and increased chances of successful predation of solitary limpets. Possible explanations for this choice are discussed. This preference for attacking solitary 1:impets may have important unpl~cations for rocky shore dynamics by shaping the spatial patterns of limpets. This may then ~nfluence the probability of Fucus germlings escaping limpet grazing.