Re-establishment of an endangered subspecies: the Norfolk Island Boobook Owl Ninox novaeseelandiae undulata

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Abstract
Summary: The Norfolk Island Boobook Ninox novaeseelandiae undulata is confined to the small, isolated Norfolk Island group, an Australian territory. On morphological and biogeographical grounds, it is here classified as a large, distinctive subspecies of the New Zealand Morepork N. novaeseelandiae. In 1986 only one specimen, a female, survived. A shortage of large trees with suitable nesting holes appeared to be the immediate problem. The Australian Nature Conservation Agency, islanders and New Zealand wildlife authorities have cooperated in an attempt to re-establish an owl population in situ. Nest-boxes were erected in trees in the area frequented by the female and were used readily as roosts. In September 1987, two male New Zealand Moreporks were introduced. The female paired with one male and produced four hybrid F offspring (in 1989 and 1990). Two of these paired in mid-1991 and have since produced five F offspring (two in 1993 and three in 1994). The original female remains paired but now appears to be reproductively senile. At present there seems to be a shortage of mature males, since two female offspring are paired and both lay eggs and attempt to incubate them in the same nest; and a lone female has established a territory. In early 1995 all eleven owls appeared to be alive in the wild. The effort is low-cost, requires relatively little manpower, is carried out with minimal disturbance to the owls, and goes hand in hand with other conservation programmes.