Mass mortality of adult Common Toads at two breeding sites in Yorkshire

摘要

Common Toads Bufo bufo characteristically assemble in large numbers at traditional breeding pools in early spring. This may make them susceptible to predation but noxious chemicals secreted by the skin, especially by large parotid glands behind the head, coupled with the habit of individuals to inflate the body and stretch out the legs when threatened, may give a measure of protection (Bedford, 1974; Ewert & Traud, 1979). However, field observations indicate that some predators may not be deterred, leading to instances of mass mortality of adult Common Toads. This amphibian is known to be declining in Britain and is listed in section 41 of the Natural Environment and Rural Communities Act 2006 as a "species of principal importance for the purpose ofconserving biodiversity". Therefore, investigation of sources of adult mortality is relevant to the conservation of this species. This article describes incidents of large-scale predation of Common Toads at two breeding sites in Yorkshire and compares them with similar incidents in the UK and elsewhere.