Abstract
The importance of light as a regulating factor of the sexual cycle in birds has been demonstrated by Rowan1 (junco), Bissonnette2 (European starling), Miyazaki3 (Zosterops palpebrosa) and Kirschbaum4 (English sparrow). These investigators have observed a precocious development of the testes following daily increases in the period of illumination. Such experiments were usually carried out during the early winter. The present author has undertaken to determine whether lengthened daily periods are equally effective at a time further removed from the normal breeding season. In this paper, a group of male sparrows, exposed to additional light beginning November 18th, is compared with another group first exposed on September 30th.The November group of sparrows had been in the laboratory 16 days previous to the artificial lengthening of the days and all possessed the horn-brown bill of the sexually quiescent period. The birds received 4 1/2 additional hours of light, daily, from a 100-watt incandescent bulb thro...
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
