Distraction displays of red grouse in relation to risk of predation.

Abstract

By performing spread-wing distraction displays adult Red Grouse Lagopus lagopus scoticus feign injury and attempt to draw predators away from their offspring (Pedersen & Steen 1985). A characteristic of distraction displays is a large variation between years although the cause of such variation is not clear. A number of hypotheses have been proposed to account for this variation but these can be considered as two broad types.

First the 'Risk of predation' hypothesis proposed by Armstrong (1942) states that: The frequency of distraction displays was a response to the risk of predation on the offspring with an increase in distraction display with offspring vulnerability.

Second the 'Cost of replacement' hypothesis proposed by Barash (1975) and corrected by Harvey & Greenwood (1978) states that: The frequency and/or intensity of distraction display increases with the parental investment required to replace chicks lost to a predator.

This study provides some preliminary analysis of data in relation to these two hypotheses. More detailed analyses will be conducted and published elsewhere (Hudson & Newborn In press).