A difference in production and associated events in two races of spruce grouse

Abstract

Analyses are given for several parameters in the production of juvenile spruce grouse in a local population in southwest Alberta (Canachites canadensis franklinii), 1970–1975, and in northeast New Brunswick (C. c. canace), 1975–1980. Canachites c. canace exhibited greater clutch size, nest success, proportion of females with broods and production of juveniles. Hatchability of eggs, average brood sizes, and mortality rates of juveniles were similar. Differential nest success appeared to be a primary influence on the difference in production of juveniles. In autumn, canace exhibited a substantial net reduction in juveniles as a consequence of dispersal, but not franklinii. Densities of juveniles in winter were similar. Speculation is provided about the differences in production and their association with other aspects of life history, notably the quality of juvenile stock.