Kirby J.S., Gilburn A.S. & Sellers R.M. (1995) Status distribution and habitat use by Cormorants Phalacrocorax carbo wintering in Britain. ARDEA 83 (1): 93-102

This paper describes a study of Cormorants wintering in Britain based on information collected as part of the National Waterfowl Counts scheme for the four winter seasons from 1987/88 to 1990/91. Birds were found to be widely distributed throughout Britain, both inland and on the coast, with the greatest concentrations in southeast England, northwest England and south-west Scotland. Evidence is presented which suggests that Cormorants switch from coastal to inland habitats through the winter so that by February only 50-54% of birds were found on coasts. The total winter population is estimated to have reached c. 19 000 in 1990/91, and has increased by 74% overall. Possible reasons for these changes are discussed.