Time Budget and Pair-bond Dynamics in the Comb-crested Jacana Irediparra gallinacea: A Test of Hypotheses

Abstract

The mating system and time budgets of colour banded Comb-crested Jacanas were studied at two sites near Townsville, Queensland, Australia. These Comb-crested Jacanas were polyandrous. Females copulated with an average of 2.6 males and produced clutches for an average of 1.8 males during a breeding season. The pair bonds of Comb-crested Jacana displayed some flexibility. Males with which a female copulated might be chased off territories before receiving a clutch; males who lost a clutch might change mates after the loss; and females might be replaced by another who took over all her males. The female time budget of activity did not change substantially with the onset of breeding except for the inclusion of reproductive behaviours. Males significantly decreased the time spent foraging and significantly increased the time spent in other somatic behaviours with the start of breeding. As breeding progressed, males significantly decreased the amount of time spent in non-foraging somatic behaviours and further reduced the amount of time spent foraging once they had a clutch. Males incubated for an average of 54% of their time when clutches were complete, and females almost never incubated. Hatching success rate was very low; 80% of nests were lost before hatching. The observations and time-budget data best support the replacement-clutch hypothesis for the adaptiveness of polyandry in the Comb-crested Jacana, although the female-energetic hypothesis can not be rejected completely.