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Providing evidence to improve practice

Individual study: The effect of nutritional supplements on egg production of kakapo Strigops habroptilus on Codfish and Pearl Islands, New Zealand

Published source details

Houston D., Mcinnes K., Elliott G., Eason D., Moorhouse R. & Cockrem J. (2007) The use of a nutritional supplement to improve egg production in the endangered kakapo. Biological Conservation, 138, 248-255


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Provide supplementary food for parrots to increase reproductive success Bird Conservation

A small study on Codfish and Pearl Islands, South Island, New Zealand, during 1997–2005 (Houston et al. 2007), found that kakapos Strigopus habroptilus fed with food pellets (specially formulated to provide nutrients missing from kakapos’ diets) laid larger clutches than those provided with either nuts (almonds, walnuts, Brazil nuts and honey-water) or no supplementary food (76% of 29 pellet fed birds having 3-4 eggs/clutch and an average of 2.76 eggs/clutch; 33% and 2.22 for nine nut-fed birds; 33% and 2.00 eggs/clutch for three unfed birds). However, fed birds did not nest more frequently than unfed birds, with nesting apparently related to the fruiting of rimu Dacrydium cupressinum trees. Food was either fed ad libitum or was 20 g of nuts every three days or 50-150 g of pellets every three days year-round.