The use of a nutritional supplement to improve egg production in the endangered kakapo

The critically endangered kakapo (Strigops habroptilus) is intensively managed on offshore islands off New Zealand. The birds rear their young on the fruits of native trees. These trees produce abundant fruit only every 2-6 years, and kakapo only breed in those years. At other times their natural diet is poor in nutrients. This study investigated the effect on breeding of improving kakapo nutrition by the provision of two dietary supplements: a nut supplement and a specially formulated pellet. Although dietary supplements had no effect on nesting frequency, females that took the specially formulated food pellets laid significantly larger clutches than those that did not. The supplementary diet of nuts did not increase egg production, which suggests that egg production in kakapo is limited by the nutritional quality of their natural diet rather than the energy content.