Feeding-Behavior and Diet of Double-banded Plovers Charadrius bicinctus in Western Port, Victoria

Abstract

The feeding behaviour and diet of Double-banded Plovers Charadrius bicinctus were studied in Rhyll Inlet and on the Churchill Tidal Flats in Western Port, Victoria, in autumn and winter. The birds preferred feeding in sandy (40%), light eelgrass (33%) and sandy-mud areas (27%). They showed a distinct horizontal distribution when feeding, with 88% on wet substrates above the water's edge and 10% at the water's edge. Two feeding modes were employed: isolated pecks and multiple pecking and probing. Pecks were the primary feeding actions observed during daylight. The alternative feeding mode of bursts of multiple pecks (with occasional probes) was observed close to dusk and inferred from tracks in the mud to be commonly used after dark. The mean duration of feeding periods in intertidal areas was 329.4 minutes per diurnal tidal cycle (s.d. ± 93.3). although in some circumstances, these periods were supplemented by feeding in non-tidal areas. The mean peck rate of Double-banded Plovers feeding in single-peck mode was 0.41 pecks per second (s.d. ± 0.17) and, in the multiple-peck mode, 0.22 pecks per second (s.d, f 0.04). The most significant prey species from intertidal areas was the Sentinel Crab Macrophthalamus latifrons. The adaptive significance of the feed- ing behaviour of the birds is discussed in relation to physical constraints on feeding and the behaviour and ecology of their main prey.