Shetland beached bird surveys: national and European context

Abstract

SynopsisA Shetland-wide beached bird survey was established in March 1979 and monthly surveys have continued since. This paper presents results from March 1979 to December 1992 during which time a total of 34 320 corpses of seabird and seaduck were found, of which 34023 (99.1%) were specifically identified. Corpses of guillemot (8911), fulmar (8707), kittiwake (4421), herring gull (2264), shag (1843) and great black-backed gull (1785) comprised 82.1% of the identified total, the remainder being made up of 31 other species. The relationship between the numbers of each species found, and their numbers and occurrence in Shetland waters is discussed. A total of 2781 corpses were judged to have been oiled before their deaths, of which 2732 (98.2%) were specifically identified. The six species most frequently found oiled were guillemot (1170 corpses), fulmar (543), kittiwake (184), razorbill (131), puffin (111) and shag (99).Variations in both the percentage of corpses found that were oiled, and the number of oiled corpses found per kilometre of beach surveyed, are examined and discussed. Comparison is made with results from beached bird surveys elsewhere in the British Isles and in other countries bordering the North Sea. In some species, notably the pelagic auks, there was considerable annual variation in the numbers of unoiled corpses found while in other species the number of unoiled corpses found changed more gradually over the 14 years. Reference is made to similar changes observed in other beached bird surveys and possible reasons for these changes are discussed.