Monitoring breeding outcomes of cryptic nocturnal species such as the North Island brown kiwi (Apteryx mantelli) is an important aim for conservation management in New Zealand. While fitting male kiwi with radio transmitters enables incubation burrows to be found and monitored, it is invasive and expensive. Remote monitoring methods (without handling of birds) are preferable.
Incubation behaviour varies among the different taxa of kiwi. For North Island brown kiwi (Apteryx mantelli) and little spotted kiwi (A. owenii), only the male incubates the eggs, except for in the first week. Meanwhile, for Okarito brown kiwi (A. mantelli) and the tokoeka (A. australis), incubation is shared by both sexes. In addition, amongst southern tokoeka, family group members can assist with incubation to the extent that breeding males may take no part in incubation at all.
Incubation temperatures of the great spotted kiwi were studied by telemetry methods at the Otorohanga Zoological Society in October 1989. The male maintained the core temperature of the egg at about 28-31.8-degrees-C. When he emerged to feed at night, the female started to incubate. She did not have a brood patch, but could heat the egg to 28-28.5-degrees-C, sufficient for embryo growth. Some of the reasons why female great spotted kiwi might help with incubation are discussed.