Body condition of gray partridge (Perdix perdix) during fall and winter in Saskatchewan

Abstract

During August 1979 to March 1980, 118 Gray Partridge were collected from a 207[superscript 2] km study area near Tugaske, Saskatchewan. Temperature and snowpack information were monitored throughout the study period. Partridge were necropsied, searched for internal and external parasites, and fat, protein and moisture determinations conducted for each bird. Mean monthly temperatures during the study period approximated the 30 year mean for the area. The winter of 1979 - 80 was characterized by reduced snow depths and a longer snowfree period than normally occurs in this area of Saskatchewan. Male and female partridge exhibited a similar seasonal pattern of body weight fluctuation during the study period. There were no significant differences (P>.05) in mean monthly body weights of adult and subadult male partridge during August to March. Female partridge weights increased significantly (P<.05) from September to January, then declined through to March. Body weight of male and female partridge attained January maxima of 416 g and 410 g, respectively and are among the highest recorded in North America. The application of several condition indices failed to provide more accurate estimates of metabolic reserves than carcass weight alone. Lipid reserves appeared to be of significant metabolic importance to Gray Partridge in Saskatchewan. Among male Gray Partridge,peak fat reserves (29% dry body weight) occurred in January and among females, in December (30% dry body weight). There was no significant difference (P>.05) in mean monthly weight of body fat of male partridge. Body fat increased significantly (P<.05) among females between September and December. Thereafter, fat reserves in both male and female partridge declined but not significantly, to the end of March. Subcutaneous fat deposits constituted the largest fat reserve in partridge, comprising 53% and 48% of total body fat in males and females, respectively. Carcass protein levels in both sexes were relatively constant during the period of study. Weight of the abdominal fat depot represented a practical, easily obtained and relatively accurate predictor of total body fat reserves, while carcass weight was the best predictor of protein reserve in Gray Partridge. Endoparasite and ectoparasite loads were not overly large among partridge examined and appeared of no significance as a mortality factor. The implications of these findings to partridge management are discussed.