Fig. 3

Nest availability analysis: dashed line represents a = 1 suggesting choice of partner was equal to the proportion of occupied nesting sites (nest boxes containing one or several litters), if a < 1 females choose communal (1) more often than random expectation and, if a > 1 females choose solitary (0) more often than random. Potential values for a are represented by the light grey lines. For the raw data we find a value of a = 1.3, here represented by the red line (± 95% CI polygon). Tick marks represent the variability in the proportion of occupied sites