Wildlife Damage Management, Internet Center for


Date of this Version



Published in Proceedings of the 11th Wildlife Damage Management Conference. (D.L. Nolte, K.A. Fagerstone, Eds). 2005.


Due to increasing human-wildlife conflicts with birds and growing opposition to lethal techniques, nonlethal methods need to be developed to help manage bird populations. DiazaCon™ is a promising oral contraceptive that acts by directly inhibiting the conversion of desmosterol to cholesterol. Because cholesterol is essential for the production of the steroid reproductive hormones testosterone, progesterone, and estradiol, DiazaCon™ also indirectly inhibits the formation of these hormones. These hormones are essential for sperm and egg production, and the production of egg yolk precursors in the liver. Because DiazaCon™ is cleared slowly from the liver, its contraceptive effects are long-lasting. Initial research with Coturnix quail (Coturnix coturnix) helped determine DiazaCon’s mechanism of action. Further research showed efficacy in monk parakeets (Myiopsitta monachus) and mallards (Anas platyrhynchos). Brown-headed cowbirds (Molothrus ater), American crows (Corvus brachyrhynchos) and ring-necked doves (Streptopelia risoria) were also studied as potential candidates for DiazaCon™ contraception. Mallards and ring-necked doves were used as model species for Canada geese (Branta canadensis) and pigeons (Columba livia), respectively. DiazaCon™ application over a very short time results in long-lasting contraceptive effects, an advantage for target species, but a disadvantage for nontarget species. Care must be taken when delivering DiazaCon™ to determine what nontargets are present and how best to avoid them. Timing of delivery is also critical to ensure maximal reproductive effects, and information on the reproductive cycles of the species of interest is needed.