Breeding of the bellbird on the Poor Knights Islands, New Zealand

Abstract

The breeding of the bellbird (Anthornis melanura) was studied intensively over three seasons on Aorangi Island, Poor Knights Islands. Adult males defended territories all year but ventured beyond them to exploit localised food resources and to obtain water; some adults defended the same territory for at least 5 years. Adult females shared a territory with a male only during the breeding season. At other times of the year adult females were joined by juveniles and immatures and formed feeding flocks. The breeding season extended from late September to late December. A few nests were built on the ground but most were in dense vegetation, usually near the canopy. Peak egg-laying extended from mid-October to mid-November and only one clutch of two to four eggs was laid. Nest building and incubation were completed by the female alone but both parents fed nestlings. Fledglings stayed in the vicinity of the nest for several days, and were fed by both parents. Incubation and nestling periods were about 15 and 19 days respectively. Comparisons are made with the breeding biology of bellbirds and other native passerines on mainland New Zealand, and the importance of the predator-free enviomment of the Poor Knights Islands is stressed.

Keywords:

• Anthornis melanura
• Meliphagidae
• Poor Knights Islands
• offshore Islands
• reproduction
• life history strategy
• predator-free environment