Seasonal Abundance and Diet of the Comb-crested Jacana Irediparra gallinacea in the Tropical Northern Territory

Abstract

From 1981 to 1984, Comb-crested Jacanas were seasonally abundant on the freshwater floodplain of Magela Creek in the monsoonal Northern Territory. Densities tended to be low during the wet season and increased during the dry to annual maxima in August–September. Comb-crested Jacanas ate a wide variety of invertebrate and plant material. Aquatic invertebrates and seeds of aquatic plants dominated the diet by dry weight. Seeds of water-lilies Nymphaea spp. (Nymphaceae) and aquatic moth larvae (Pyralidae: Lepidoptera) were particularly important. Plant and animal material of terrestrial origin was important in some samples. Sexual differences were evident in morphology. Females were heavier, and had longer bills and wider gapes. Despite these morphological differences there was little evidence of differentiation in diet between males and females.