The Wildlife Toxicology Division of the Canadian Wildlife Service is investigating the epidemiology of congenital anomalies in colonial birds, particulary gulls and terns. Investigators and banders are asked to provide GLEN A. FOX, Wildlife Toxicology Division, Canadian Wildlife Service, National Wildlife Research Centre, Ottawa, Ontario, Canada KIA OE7, with the total number of young handled or banded per location, by species, per year, and the number and nature of young with anomalies (crossed or abnormal bills, extra digits or otherwise deformed feet, missing or abnormal eyes, etc.). When dead, such chicks should be preserved in alcohol or formalin if possible, for further study.