Wildlife Damage Management, Internet Center for


Date of this Version



Proceedings Ninth Bird Control Seminar, Bowling Green State University, Bowling Green, Ohio, October 4-6, 1983. Ed. William B. Jackson and Beth Jackson Dodd


Copyright © 1983 André Cyr and Diane Lacombe


To evaluate the importance of the timing of an application of a chemosterilant, we measured the effect of Ornitrol on testis size and maturation of sperm cells at different time periods during testis growth and in two different breeding seasons. Indoor experiments showed that Ornitrol did not affect testes nor sperm cells when applied at the onset of testes growth. but did have an effect when applied the 4th week afterwards. Field experiments showed much variation in Ornitrol treatment efficiency between years. Timing of application in relation to testes growth is believed to be of major importance in using chemosterilization as a management tool for red-winged blackbird population control.