Fall and Winter Weights of Hungarian Partridges and Sharp-Tailed Grouse from Alberta

Abstract

Weight changes of male and female Hungarian partridges followed a similar trend during October-March (Fig. 1). This mixed-age sample yielded no significant differences in mean monthly weights between the sexes. Weight increased continually from October to January, and declined thereafter; the 7 per cent weight loss during February and March approximately equaled the earlier gain. Weight changes of both adult and juvenile partridges exhibited the same general pattern, although juveniles seemingly reached their peak 1 month later (Fig. 2). I think one might safely conclude from these data that mean monthly weights of juveniles gradually approach, and by February attain, those of adults. Male sharp-tailed grouse gained weight over the period September-December, but lost steadily during January-March (Fig. 3). Mean monthly weights of female sharptails, on the other hand, were essentially stable from October through January. Females weighed considerably less than males in the months of November, December, January, and February. A tendency for weights to peak during December-January has already been reported in such other gallinaceous game birds as bobwhite quail (Colinus virginianus) (Robinson, 1957; Hamilton, 1957), ruffed grouse (Bonasa umbellus) (Marshall and Erickson, 1945; Bump, et al., 1947), and prairie chicken (Tympanuchus cupido) (Hamerstrom, 1941). According to Koskimies (1958), weights of capercaillie (Tetrao urogallus) and blackgame (Lyururus tetrix) in Finland show a November maximum. Manweiler's (1939) information on Minnesota sharptails suggests a decrease in weight from early November to early January, followed by an increase through March almost the reverse of that displayed by Alberta birds. I can offer no explanation for this apparent difference. The more pronounced rise and fall in male vs. female weights among Alberta sharp-tailed grouse is seen also among red grouse (Lagopus scoticus) in Great Britain (Wilson, 1911).