Breeding Biology and Behavior of the Willie Wagtail Rhipidura leucophrys in the Madang Region, Papua New Guinea

Abstract

Ten breeding pairs of Willie Wagtail Rhipidura leucophrys were sedentary and territorial (average territory size 0.85 ha) from 16 September-6 December 1990, at the end of the dry season and the beginning of the rainy season, an important part of the Willie Wagtail breeding season in Papua New Guinea. Nine of 15 nests found were built over water; they were 1-14 m above ground or water. Most were cup-shaped, easy to find but difficult to climb to. Both parents built the nest. During laying eggs were incubated 70- 80% of the time, mostly by the female. Later, the eggs were incubated for 90% of the daytime and female sitting dominance was not so clear. One-day-old nestlings were brooded most of the day; this decreased as the nestlings grew and after day 7 became minimal. During the first three days of nestling life the male shared brooding; his share decreased later. Both parents equally fed the nestlings. Visits with food per hour varied from 5-26, and increased with nestling age. Males and females foraged in the same places, within 1-200 m of the nest, usually not more than 70 m away. Patterns of post-natal growth in the Willie Wagtail are similar to those of other passerines. Eight different hunting techniques were distinguished. Parent birds spent most of their time at the nest which they defended rather than concealed. Peak singing activity was just before sunrise.