Life history studies of the Lesser Snow Goose (Anser caerulescens caerulescens) : I. The influence of age and time on fecundity.

In many species, fecundity is dependent on age. For some populations - particularly those exploiting temporally variable environments - these age-specific fecundities may themselves vary with time. In this report, we investigate the general effects of age and time on clutch size in a wild population of Lesser Snow Geese (Anser caerulescens caerulescens). We show that both factors affect clutch size independently. Age effects are confined almost exclusively to the two, three and four year old age classes. Mean clutch sizes of all age classes show considerable inter-seasonal variation. These temporal differences in fecundity will ultimately influence the dynamics of the population. In particular, they imply that there will be no convergence to a constant growth rate or a stable age distribution.