Sex differences in incubation behaviour but not mortality risk in a threatened shorebird

Sex-related variation in survival is common in birds and, as it influences effective population size and population growth, is important for conservation and species management. Here we assessed incubation behaviour and sex-related survival in a threatened sexually monomorphic shorebird, the St Helena Plover Charadrius sanctaehelenae. Males incubated at night, the period of highest activity of cats, which are likely to be predators of breeding birds. In spite of behavioural differences between the sexes, adult survival was not significantly different between males and females, suggesting that sex-biased behaviour need not lead to sex-related survival, and thus behavioural differences may not impact upon the adult sex ratio.