Status of Golden Eagle Aquila chrysaetos in Britain in 2003

Abstract

Capsule The third complete survey of Golden Eagles in Britain found 442 pairs. Aim To investigate the population size, distribution and breeding success of Golden Eagles in Britain, for comparison with similar surveys in 1982–83 and 1992. Methods All known home-ranges were surveyed between January and August 2003, to record Golden Eagle presence, breeding attempts and productivity using a three-visit methodology. The first visits were made in January–March to look for the presence of eagles, the second in April–June to detect whether a breeding attempt was taking place and the third in July–August to establish breeding success. Results In total, 442 pairs were located, a slight increase on the numbers in 1982–83 and 1992. There was considerable variation in population trends at a regional level, with decreases since 1992 in the eastern and south-central Highlands but an increase in the Hebrides. The mean productivity in 2003 was 0.36 fledged birds/pair. There was significant variation in breeding success between regions with, as in previous surveys, productivity being highest in the eastern Highlands. Conclusion The British Golden Eagle population remains stable. There remain concerns regarding the future of this population, particularly due to the threat posed by illegal persecution, and these results provide some supporting evidence for concerns raised by previous analyses. Persecution related to grouse moor management could be depressing the population in the eastern Highlands, preventing expansion into suitable habitat still unoccupied, and may be reducing the pool of non-breeding adult ‘floaters’ which act as a buffer against adverse population impacts. However, the survey did detect increases in the Hebridean islands since 1992, which may be because of a reduction in persecution.