The ecology of yellow‐crowned parakeets (Cyanoramphus auriceps) in Nothofagus forest in Fiordland, New Zealand

Abstract

Yellow‐crowned parakeets (Cyanoramphus auriceps) were studied in the Eglinton Valley, Fiordland, New Zealand. Productivity and mortality were closely related to cycles of beech seeding. Following a heavy beech mast, parakeets fed extensively on beech seed, and bred not only during their normal late summer breeding season, but right through the following winter, spring, and summer. During this time, the parakeet population increased dramatically, but in the following autumn it declined sharply, probably as a result of the depletion of beech seed and high rates of predation by stoats and perhaps other arboreal predators. Nesting parakeets are very vulnerable to stoat predation because they are hole‐nesters and because their chicks are very noisy just before fledging. Stoat trapping during a stoat irruption seemed to be of no benefit. Although trapping reduced stoat population density, enough stoats remained to prey on all accessible parakeet nests. More extensive trapping, and trapping when stoat numbers are relatively low, are more likely to benefit parakeets.

Key words:

• yellow‐crowned parakeet
• Cyanoramphus auriceps
• beech mast
• population irruption
• breeding
• nest dimensions
• radio tracking
• stoat predation