Population densities of mountain hares compared with red grouse on Scottish moors.

The population densities of mountain hares Lepus timidus L. were compared with those of red grouse Lagopus l. scoticus (Lath.), within and between study areas on heather Calluna vulgaris (L.) Hull moors in north-east Scotland. Mean densities varied greatly between different areas, in both hares and grouse. They were higher on the areas where the underlying rock was richer and the heather was more nutritious. The amplitude of population fluctuations differed greatly between different areas in both species. The amplitude was generally bigger in hares than grouse. Fluctuations of the two species were not in phase within areas. Within each species, population fluctuations were not in phase on different areas. [ABSTRACT FROM AUTHOR]