Patterns of density dependence within and between populations of red grouse Lagopus lagopus scoticus in Britain
Robertson, P.A. & Hudson, P.J. 1997: Patterns of density dependence within and between populations of red grouse Lagopus lagopus scoticus in Britain. - Wildl. Biol. 3: 292.
Red grouse Lagopus lagopus scoticus populations were monitored by pre and post-breeding counts at over 40 sites in Northern England and Scotland. Counts were conducted for at least five consecutive years per site. These data were used to examine within and between site patterns of density dependence in adult loss during winter and summer, and loss of potential production. There was evidence of density-dependent adult loss on a within-site basis in both winter and summer; losses were highest in years when population density was high. There was no evidence of between-site density dependence during either period; high and low density populations demonstrated similar average rates of winter and summer loss. There was no clear pattern of breeding loss on a within-site basis but evidence of between-site density dependence; sites with higher breeding densities of grouse had lower rates of breeding loss.
Key words: density dependence, Lagopus lagopus scoticus, Northern England, red grouse, Scotland
Peter A. Robertson, The Game Conservancy Trust, Crubenmore Lodge, Newtonmore, Inverness-shire, Scotland, PH20 1BE, United Kingdom
Peter J. Hudson, Unit of Wildlife Epidemiology, Department of Biological and Molecular Sciences, University of Stirling, Scotland, FK9 4AL, United Kingdom