BRANTA — S. James Reynolds
Condition as an indicator of the requirements for reproduction in female Spruce Grouse (Dendragapus canadensis)
Institution: University of Toronto, Canada
Supervisors: J Bendell
Details: MSc 1993(Completed)
Address: School of Biosciences, The University of Birmingham, Edgbaston, Birmingham, UK B15 2TT (Oct 2005) Email
Subject Keywords: Body size, condition, reproductive biology, reproductive physiology
Species Keywords: Spruce Grouse Dendragapus canadensis
Two hypotheses were examined: 1. adults have greater clutch sizes than yearlings because they are in better nutritional condition for reproduction; 2. territory occupancy in yearlings is related to condition. These hypotheses were tested by investigating body condition of 72 hens from northeastern Ontario. Condition measures (body and breast muscle masses) declined from prelaying (early spring) to postlaying (incubating, brooding and post-fledging) hens. No age-related differences in condition were revealed. Atrophy of breast muscles explained over 30% of the decline in condition over this period. Condition of hens in all postlaying categories was similar. Surplus and territory-holding birds were also in similar condition. Declines in calcium and phosphorus accounted for loss in bone mass from prelaying to postlaying birds. Condition differences do not account for age-related reproductive success or territory occupancy in Spruce Grouse hens.
Reynolds, S.J. 1996. Establishing body-size indicators in a study of female spruce grouse Dendragapus canadensis. Journal of Zoology 240: 113-122.
Reynolds, S.J. 1997. Body condition, territory ownership and age-related reproductive performance in Spruce Grouse Dendragapus canadensis hens. Ibis 139: 646-651.