VARIATION IN MATERNAL INVESTMENT IN A SMALL CERVID - THE EFFECTS OF COHORT, SEX, LITTER SIZE AND TIME OF BIRTH IN ROE DEER (CAPREOLUS-CAPREOLUS) FAWNS

We investigated the effects of cohort, sex, litter size and time of bi rth on birth weights and postnatal growth rates of roe deer fawns in a highly reproductive Norwegian population. By repeatedly recapturing r adio-collared individuals, a total of 950 weights were obtained from 2 31 fawns of known age. In accordance with earlier studies, there was a period of linear growth during the first month following birth. Mean postnatal growth rates of 155 g/day are the highest yet recorded for r oe deer; however, the mean birth weights of fawns were lower than thos e reported from populations in continental Europe. During the period o f linear growth, we found no sex differences. However, growth rates we re affected both by time of birth and litter size; fawns born early ha d lower growth rates than fawns born during or after the peak calving period, and fawns in triplet - groups had lower growth rates than eith er fawns in twin - groups or single fawns. Despite a fourfold increase in population density during the study, this factor was not able to e xplain variation in postnatal growth rates, although cohort effects on birth weight were evident.