Evidence for an endogenous circannual component in the control of the annual gonadal cycle in spotted munia

For the first time evidence has been provided for a circannual gonadal cycle in any avian species (male spotted munia Lonchura punctulata, Estrildidae) held on continuous light. A model has thus been rendered available in which the “entraining effects” of photoperiod could be clearly distinguished from its direct “driving effects”.