The Role of Darkness in Sexual Activity of the Quail

Changes in Seasonal Egg Production of Turkeys Induced Through Controlled Light Exposure and Force Moulting

“…Short daily light periods, are required to end the refractory period according to Damste (1947) and Wolfson (1952). Kirkpatrick and Leopold (1952) in experiments with quail concluded that night or dark periods exert a specific influence on photoperiodic response. Farner, Mewalt and Irving (1953) working with sparrows using light exposure at 10, 12.2, 18 and three other 10 hour groups with light interruption of dark periods, found equal stimulation of gonads from 18 hours of continuous light and 10 hours interrupted by nine periods of 1.11 hours of darkness.…”

Photoperiodic and physiological adaptations regulating avian breeding cycles and their ecological significance

“…An exception is the Japanese quail, where young females under long daily photoperiods, develop to full reproductive condition (Follett & Farner, 1966b). It is unnecessary to dwell here on the controversy following the submissions of Kirkpatrick & Leopold (1952 and Jenner & Engels (1952) that the period of darkness was the inhibitory factor preventing a gonad response. The ingenious manipulation of light/dark schedules undertaken by Wolfson (see Wolfson, 1959 for summary) demonstrate that the effective stimulus follows reactions initiated in the light phase of the cycle.…”

Role of Light in the Progressive Phase of the Photoperiodic Responses of Migratory Birds

“…From the results of their studies Kirkpatrick and Leopold (1952) This was brought out particularly by the 12L-16D schedule in the first experiment. Not only did the birds respond, but the duration of the response was longer than normal and characteristic of 12-hour photoperiods (Wolf son, 1952b(Wolf son, , 1959b.…”

“…(See Wolfson, 1959a, 1959b for review and references. )The observations that interruption of the long night of a short day with a brief period of light during the progressive phase results in a rate of response comparable to that of a long day (Kirkpatrick and Leopold, 1952;Jenner and Engels, 1952) and that administration of the same total photoperiod in smaller doses induces a more rapid response (Wolfson, 1953), raised the question of…”