Generalized linear mixed models for the potential effects of group size and biomass density upon the age of first parturition (P1), offspring survival (ISURV), and interbirth intervals with offspring that survive to reach weaning age (IBI).

The identity of the group was included as a random effect in all analyses. The identity of the mother was included as a random effect in the analyses of ISURV and IBI, but not P1 because that analysis involved only one data point per mother. NGRP, NMOM, and NDATA are the number of groups, mothers, and total data points involved in each analysis. Although the relationship between group size and IBI is nearly significant, it is in the opposite direction of predictions for feeding competition. No significant results emerged from multivariate analyses, including when we added an interaction term (biomass/group size).