A field study of the breeding biology of the little spotted kiwi (Apteryx owenii) with emphasis on the causes of nest failures

Abstract

The breeding biology of the endangered little spotted kiwi Apteryx owenii was studied over a period of seven years on Kapiti Island, New Zealand, Breeding began in spring, with some laying continuing into summer and autumn, Some behavioural displays between members of a pair were recorded. Twenty five of the 31 nests found were underground in burrows dug by the kiwis or in natural cavities. The remainder were in logs or thickets of vegetation. The ratio of one to two-egg clutches was estimated to be 7:1. There was little or no nest preparation before laying, but the incubating birds covered the entrances of the more conspicuous nests with leaf litter. Only the male incubated, and he left the nest unattended for one or two days at a time in the first ten days after laying and for up to six hours at night during full-time incubation. I consider that cooling of the egg is a reason for the long incubation period of between 63 and 76 days. Chicks were not seen to be fed by their parents and left the nest at dusk to forage unaccompanied. Males shared the nest with the chick during the day for about three weeks after the chicks first emerged. The pairs under study usually bred each year, but productivity was only 0.08 independent young per breeding pair per year. Probably 60% of losses were due to predation by wekas (Gallirallus australis). The evolution of the breeding strategy of kiwis in the presence of a predator is discussed.

Keywords:

• ratite
• breeding biology
• nest losses
• predation
• productivity
• endangered species