Why budgerigars breed in continuous darkness



Budgerigars (Melopsittacus) exposed to male vocalizations will breed in total darkness, and the possibility arises that darkness is stimulatory. The present experiments showed that the availability of a nest-box accelerates egg-laying, and that relative darkness is an important property of a nest-box. Furthermore in the absence of a nest-box breeding occurs sooner in continuous darkness than on 14 L: 10 D. Intermittent periods of darkness imposed in the light period of a 14 L: 10 D regime accelerate egg-laying somewhat.