Bald Knob, Arkansas - U.S. Fish and Wildlife officials announced Monday that final diagnostic results had been received concerning the recent snow and Ross’ goose die-off at the Bald Knob National Wildlife Refuge. After the dead geese were discovered on Jan. 9, specimens were immediately collected from the refuge and shipped to the National Wildlife Health Center for complete necropsies to confirm the cause of death.

Wildlife pathologists from the NWHC diagnosed the cause of death in the snow geese to be aflatoxicosis and not avian cholera as originally suspected. Aflatoxins are produced by fungi of the genus Aspergillus and occur in cereal grains, including corn which was found in the crop and gizzards of the collected geese.

Most species of mammals and birds are susceptible to aflatoxicosis, but there are differences in mortality among species and between age classes of animals. There is no medical treatment for aflatoxicosis, and prevention is the key to minimizing wildlife losses. Heat and drought, such as occurred in many areas of the Southeast this summer, provides optimal conditions for growth of this fungus.

U.S. Fish and Wildlife officials collected and disposed of approximately 869 dead geese which were half of the original estimated 1,300 to 1,500 when discovered. The source of the corn containing the aflatoxin found in the geese is currently unknown. The refuge does not grow corn in its cooperative farming program.

The geese apparently fed on the affected corn and flew back to the refuge to roost where they succumbed to the toxins. The outbreak was confined to snow geese and Ross’ geese with no other species of waterfowl affected.