Alastair Robertson, (Magazine, 27 December), argues that licences should be granted to “bump off” the odd buzzard that troubles pheasant shoots and to the uninitiated this may sound plausible but he fails to understand the science of population dynamics.
Any given habitat will carry an optimum number of breeding birds which is largely dependent on the availability of prey.
There will also be a number of “floaters”, namely immature and unpaired adult birds which form a pool of potential recruits to fill gaps that appear in the breeding population.
A breeding pair will also defend their territory against intruders which restricts the number of buzzards hunting over any given piece of ground, (and the pheasants).
Thus when a buzzard is “removed” its place will very quickly be taken by a “floater”, hence it is not simply a case of removing “just one bird”.
What Alastair Robertson is advocating is the systematic draining of the buzzard population. Little wonder then that Natural England has proven unwilling to license the killing of every single troublesome buzzard on every single pheasant shoot across every county in England.
Should this happen this would take us back to when the buzzard was driven to extinction in some regions through illegal persecution.
AlAstair Robertson’s weekendlife articles are always entertaining but not necessarily soundly based on nature conservation science.
Mr Robertson might usefully read Pheasants, buzzards, and trophic cascades, published under Conservation Letters 00 (2012) 1-4 and more easily readable than its title might suggest. That paper gives convincing reasons as to why ad hoc local removal of buzzards in the supposed interests of pheasant rearing would be just as likely to exacerbate losses of pheasants as to reduce them, by ignoring the buzzard’s population biology and interaction with other species.
Secretary, Scottish Raptor Study Group