Influence of environmental manipulation and nest-box availability on reproductive success of captive cockatiels (Nymphicus hollandicus)

Abstract

Environmental conditions greatly influenced breeding induced by nest-box presentation in pair-bonded cockatiels. Thirty-six pairs were first held under nonstimulatory environmental conditions for 13 weeks. To provide potential breeding cues, photoperiod, light intensity, ambient temperature, and humidity were then increased over a 12-day period; millet was replaced by a nutritionally adequate, crumbled diet; and nest-boxes were presented. Compared to previous trials performed under more constant conditions, number of pairs laying eggs, pair-day egg production, clutch size, and chick hatch weight were significantly increased.

In experiment 2, either millet or crumbled diet was fed to 36 pairs during a 9-week nonstimulatory period. Both groups were then exposed to stimulatory environments, fed crumbled diet, and presented with nest-boxes. Their reproductive performances were not different, indicating that diet change was not required to stimulate breeding.

In experiment 3, birds were fed crumbled diet throughout the trial. Nest-boxes were presented to 31 pairs during nonstimulatory conditions (group 1) or to 28 pairs during the transition to stimulatory conditions (group 2). Percent of pairs laying (85.7 v. 16.7), pair-day egg production (0.279 ± 0.036 v. 0.036 ± 0.014), and clutch size (9.1 ± 1.0 v. 4.6 ± 1.2) were greater in group 2, indicating that nest-box presentation is an insufficient stimulus to evoke maximal breeding under nonstimulatory environmental conditions.