Patterns of Grouse Shooting in Finland

Abstract

In Finland, there is a "cyclic" relationship between numbers of birds shot and the abundance of the grouse population. This cyclic pattern rotates clockwise, i.e. opposite to the classical predator-prey cycles predicted by the Lotka-Volterra equations. This means that man kills relatively more grouse during the increasing phase of the grouse cycle than in the decreasing phase. This is a sign of prudent predation. In the late 1970s, however, there may have been some overharvesting of grouse in northern Finland, partly owing to a change in the functional response (increased annual kill per hunter). The shape of the functional response curve in grouse shooting is very often concave, which is not familiar to accepted predator-prey concepts, but which is a logical consequence of the searching image concept. The functional response curve might be concave if the prey species is not particularly important to the predator. In general, not even the relatively high shooting yields in Finland seem to be correlated with population trends of different grouse species.