A study of demography and behaviour of ruffed grouse in British Columbia
Date
1973
Authors
Davies, Richard Glenn
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Abstract
A demographic and behavioural study of ruffed grouse was carried out in the central interior of British Columbia to test the null hypothesis that there was no difference in behaviouristic and demographic parameters between red and grey colour phases.
The density of the breeding population increased during the years 1968 to 1971 and decreased in 1972. The survival rates of red and grey phase males were similar. However, the abundance of red phase birds in the breeding population increased throughout the study period. Chick production varied independently of population density, being lower in late hatch years than early hatch years. Chick survival was correlated with mean maximum temperature in June. Further, the survival of broods hatched by red hens was lower than that of broods hatched by grey hens.
A comparison of three indices of behaviour: agonistic behaviour of males directed at a mirror image; approachability or flushing distance; and brood defence behaviour of hens suggested significant differences between behaviour of red and grey phases. Red phase birds interacted more vigorously with their mirror image, were more approachable, and defended their broods more vigorously than grey phase birds.
The results suggest that red and grey phase ruffed grouse differ intrinsically in certain behavioural and survival characteristics which can potentially be related to ruffed grouse population fluctuations.