Evaluations of nicarbazin-treated pellets for reducing the laying and viability of Canada goose eggs

The number of Canada geese (Branta canadensis) nesting in the United States is increasing rapidly, generating more complaints and problems associated with them. Overabundant geese can be a nuisance, threaten human health and safety, and cause damage to property. Nicarbazin (NCZ), a coccidiostat used in chicken production, has been documented to reduce egg production and viability. The reduction of reproduction through the use of NCZ could be a valuable aspect of an overall integrated goose management plan. We conducted studies at 5 sites in Nebraska in spring 2000 to evaluate the efficacy of NCZ-treated pellets for reducing the laying and viability of the eggs of Canada geese. For mated pairs of captive geese, none of the eggs (n = 20) laid by treated pairs were viable while 16 of the 20 eggs (80%) laid by control pairs were viable. At a site where resident geese did not accept the treated bait very well, there was no difference in clutch size (4.7 eggs/clutch, SE = 0.47, n = 27) when compared to a control site (4.9 eggs/clutch, SE = 0.49, n = 14, t = 2.02, P = 0.70). There was also no difference in the number of nonviable eggs/clutch at the treatment site (0.81, n = 45) when compared to the control site (0.45, n = 40, t = 2.29, P = 0.19). At a site where resident geese did consume the treated feed, only 4 eggs were laid by 55 adult females. None of these eggs were viable. Our results suggest that, when female geese receive an adequate dosage, NCZ may reduce egg viability. Further, when they receive a higher dosage, egg production can be reduced or eliminated. From this, we believe that NCZ may have the potential to be a valuable tool in the management of overabundant resident Canada geese