Day–night cycle influences the division of incubation in the Hooded Dotterel (Thinornis cucullatus)

Abstract

In species with biparental care, diel patterns in male and female incubation arise due to the differential costs and benefits of incubation. This pattern should be less obvious or absent in species where both sexes stand to benefit significantly from investing in incubation (i.e. in monogamous species with high paternity certainty), in temperate climates and in sexually monomorphic species where sexes probably experience similar physiological costs and risks of detection by predators. Despite no obvious size or colour differences between male and female Hooded Dotterel Thinornis cucullatus, males incubated significantly more at night (59% of the time), and less during the day (43% of the time). We show that despite Hooded Dotterel being sexually monomorphic, long‐lived with probably high paternity certainty, incubation is not shared equitably, with a bias towards male nocturnal incubation.