The ecology and breeding biology of morepork, Ninox novaeseelandiae, and their risk from secondary poisoning, in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Zoology at Massey University

Abstract

I studied morepork, Ninox novaeseelandiae, on Mokoia Island from November 1995 through to March 1997. Radio telemetry was a technique essential for the study of this species. Methods for the capture of morepork and attachment of radio transmitters were developed during this study. A population estimate of 25 breeding pairs was made for Mokoia. Thirty-one morepork were captured and transmitters were fitted to 21 of these birds. Both adults and juveniles were radio-tagged successfully. Morphological measurements, a blood sample and plumage descriptions were made at the time of capture. Using the morphological measurements and plumage characteristics the sex of the bird was, in most cases, unable to be determined. However, using the blood sample collected and a DNA based technique, sex could be resolved in all cases. Before this study, little was known about the ecology and breeding biology of morepork. This thesis reveals that morepork are primarily nocturnal, strictly territorial, and roost during the day amongst foliage. It has also confirmed that morepork are primarily insectivorous, but do prey on mice, Mus musculus, and birds. Breeding occurs from September through to January, and nests were located in a variety of locations. Secondary poisoning has received relatively little investigation, both in New Zealand and world-wide. The growing use of second-generation anticoagulant poisons in New Zealand conservation means that more information is needed. Seventeen radio-tagged morepork were monitored following a poison drop in September 1996, to eradicate mice from Mokoia. I followed 14 birds successfully, and of these, one died due to secondary poisoning, and a further two birds died, probably also as a result of poisoning. This thesis, therefore, provides information not only on the ecology and breeding biology of a little known species, but also information of use to conservation managers planning future poisoning operations.