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

Patellid limpets are very important grazers on NE Atlantic rocky shores, an d can occur in clumps or as solitary individuals. When oystercatchers are f oraging for limpets on rocky shores, they are often presented with a choice between solitary and clumped limpets. We attempted to establish whether oy stercatchers express a preference for limpet prey items from these differen t distributions. Oystercatchers spent far more time foraging in areas of le ss clumped limpets than in areas of clumped limpets, despite lower prey den sity. We found a strong preference for solitary prey items, and increased c hances of successful predation of solitary limpets. Possible explanations f or this choice are discussed. This preference for attacking solitary limpet s may have important implications for rocky shore dynamics by shaping the s patial patterns of limpets. This may then influence the probability of Fucu s germlings escaping limpet grazing.