Bruce Campbell’s islands revisited: changes in the seabirds of Loch Sunart after half a century
Atlantic seabirds , Volume 2 - Issue 3/4 p. 181- 194
In 1950 and 1998, counts were made of nine bird species breeding on 31 small islands in Lochs Sunart and Teacuis, sealochs that are typical of many in western Scotland. During this 48-year period, some species that were once characteristic breeding birds of islands in sealochs decreased greatly or disappeared; these included Common Eider, Common Gull, Common Tern and Black Guillemot. Numbers of Heron and Oystercatcher changed very little. Herring Gull and Great Black-backed Gull numbers both increased greatly; in recent years these increases took place at a single island at the mouth of Loch Sunart where they bred successfully. The increase in Herring Gull numbers was contrary to a wider regional trend in the period 1989-98. Records from the two lochs of seabird numbers, breeding success and causes of failure during 1990-98 suggest that two quite separate influences were at work. Excess feed from six large salmon farms may have played an important part in the local increase of large gulls, and the arrival and spread of American Mink caused the breeding failures of terns and Common Gulls that accompanied their declines. The decreases reflect changes during 1987-98 over a larger area of west Scotland, where five gull and tern species each declined by c. 40-50% following widespread annual breeding failures that are known to have been caused by mink.
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