Figure 2.

Differences in the time needed to synchronize laying for communally breeding female anis, with respect to group size (two versus three females in the breeding group) and stability (stable = all females nested together the previous year; unstable = at least one female joined or left the breeding group since the previous year). The time needed to synchronize laying is given as the number of days elapsed between the onset of laying for the first and last female in the nesting group. Boxes represent model-predicted means ± s.e.m.; whiskers represent 95% confidence intervals (n = 170 two-female groups and 37 three-female groups).