In many species of birds, the end of the breeding season is caused by the development of absolute photorefractoriness, characterised by spontaneous gonadal regression under a long photoperiod followed by a period during which gonadal maturation cannot be stimulated by further photostimulation. It has been suggested that during the dissipation of photorefractoriness under short photoperiods, birds become relatively photorefractory-that there is a gradual decrease in critical photoperiod. If true, birds should begin to respond to a very long photoperiod before they respond to a moderately long photoperiod. To test this, I transferred photorefractory castrated starlings (Sturnus vulgaris) from a long photoperiod of 18 h of light per day (18L:6D) to 8L:16D for 10, 20, or 30 days, before transferring them to either 20L:4D or to 13L:11D. There was a gradual increase in response (increase in plasma LH concentration) the longer birds had been on 8L:16D before transfer to the longer photoperiods, but there was no difference in the timing of these responses between birds moved to 20L:4D or to 13L:11D. Therefore, starlings do not pass through a period of relative photorefractoriness during the dissipation of absolute photorefractoriness.