The six hooded mergansers were found dead in Mill Stream in Winthrop recently.
A male hooded merganser swims in a bog in Bangor on Oct. 21, 2015, with a number of female hooded mergansers. Credit: Aislinn Sarnacki / BDN

Wildlife authorities in Maine said six wild ducks found dead in a stream in Winthrop have tested positive for bird flu.

The hooded mergansers were found dead in Mill Stream and tested positive for a highly pathogenic avian influenza, the Maine Department of Inland Fisheries and Wildlife said Friday.

The wildlife department said the National Veterinary Services Laboratories in Iowa confirmed the strain to be the kind circulating in Maine. The department said the strain is highly contagious and can spread and mutate between wild and domestic flocks of birds.

The disease rarely infects humans. It poses a threat to poultry operations, however. Bird flu has been detected in wild birds as well as poultry in every state in New England.

The wildlife department said Mainers who raise domestic birds should contain and separate them from wild birds whenever possible. Mainers also should be cautious about getting bird waste on clothing or boots, and should sanitize thoroughly after encountering it, the department said.

The hooded merganser is a small diving duck that is popular with bird-watchers.