Sex differences in nest construction, incubation, and parental behaviour in the polyandrous American jaçana ( Jacana spinosa)

Abstract

The polyandrous American jaçana shows sex-role reversal. Before egg-laying, males perform most nest-building movements. This behaviour primarily serves a communication rather than a building function. Some males build during incubation. Only males incubate, and incubation constancy is exceptionally low. Incubating males sit on their wings with two eggs between each wing and the breast. Males do almost all brooding; females brood occasionally after 2 or more days of rain. Although adults never feed the chicks, they feed more rapidly when accompanied by the male than when alone. Anti-predator behaviour by both sexes increases at hatching and remains high. The rarity with which females perform parental care suggests that selection has favoured behaviour that maximizes polyandry.