We used SAS 8.01 (SAs 2001) and Statistica 6.0 (StatSoft Inc 2002) for statistical analyses. Dependent variables were checked for normality (Shapiro-Wilk test), and were fitted to models using the following aying date: normal error distribution and identity link function; (2) clutch size: Poisson error distribution and log function; (3) probability of incubation, nesting success and hatch ing success (hatched nestlings/clutch size), probabil- ity of mortality or predation: binomial error distributions and logit link functions.