New Zealand Journal of Zoology abstracts

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Monitoring mohua (yellowhead) populations in the South Island, New Zealand, 1983-93

COLIN F. J. O'DONNELL

Science and Research Division
Department of Conservation
Private Bag
Christchurch, New Zealand

Abstract  The mohua (or yellowhead, Mohoua ochrocephala) is an endangered hole-nesting passerine which is now absent from >75% of its former range. This paper describes an 11 year monitoring programme, which was set up to survey 14 populations at 12 key sites throughout the range of the mohua, in order to document the pattern of population change and provide early warning of likely local extinctions. Between 1983 and 1993, one mohua population became extinct. Five of the 14 populations declined significantly, and three of these were on the verge of extinction by 1993. One population increased, and seven did not change significantly, although a declining trend was recorded at five of these. Six population crashes coincided with irruptions of stoats (Mustela erminea) following heavy beech (Nothofagus) seeding.

Keywords  Mohua; yellowhead; Mohoua ochrocephala; passerine; forests; decline; predation; population monitoring; transect counts

Received 29 August 1995; accepted 30 April 1996

New Zealand Journal of Zoology, 1996, Vol. 23: 221-228

0301-4223/2303-0221 $2.50/0   (c) The Royal Society of New Zealand 1996

PDF file of entire paper: medium quality (582K); (scanned from paper original: notes about this process)

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