Intraspecific variation of brain anatomy and drumming activity in ruffed grouse (Bonasa umbellus)

Abstract

The ruffed grouse is a widespread species, but much of its basic biology has remained understudied. I examined individual variation in two understudied aspects of their biology: brain anatomy and drumming behaviour. Individual grouse varied greatly in neuron numbers, sizes and volumes of two brains regions, so much so that sampling <6 individuals could yield inaccurate measurements. Drumming activity was also highly variable both among and within individual males. Multivariate models indicated that daily drumming activity occurred during the same week across years and hourly drumming activity peaks one hour before sunrise and one hour before sunset. Warmer temperatures also were associated with increased drumming activity, but this was a relatively weak effect compared with day of the year and time of day. Overall, these results improve our understanding of individual variation in ruffed grouse and has important implications for future studies of ruffed grouse.