European Ocean Biodiversity Information System

The main aim of the 1994/95 nearshore seabird survey in South-West England was to investigate a series of seabird sites in Devon and Cornwall previously identified as important for their wintering populations. The survey represents the first systematic study of divers, grebes, seaduck, cormorant, shag and auks within these sea areas. The number of birds recorded in the South Cornwall area exceeded criteria for international importance for great northern diver, and national importance for black-throated diver, shag and red-breasted merganser. The area also held numbers of red-necked grebe, Slavonian grebe and black-necked grebe which represented a high proportion of the small British wintering population. The Dawlish area held nationally important number of red-breasted merganser. A secondary aim of the project was to investigate ways to refine survey methods. The effect of count length on the number of birds recorded was examined by extending a sub-set of the counts. There was a marked difference in the detection rates over time for some species. A method for producing approximate correction factors was investigated. An analysis was also conducted to assess if the detectability of bird species changed in different sea states. The data showed no significant effect of sea state on the number of birds recorded.