We have had a single swan on our lake for about 6 years. Couple males were in introduced to her but did not survive. We are in the North Carolina mountains at about 3,000 ft above sea level. She has been an aggressive feeder, responding to our daily small bucket of water fowl feed immediately with some hissing , etc. There are about 25 canada geese that follow as well as Mallards and seasonal fowl such as bufflehead ducks.

Beginning yesterday she does not respond to her feed nor does she hiss when approached. Her head is on her breast with bill about and inch into the water. She does not move.

Could this be botulinum? A dog in our neighborhood has Giardia. I have not seen her throw up.

Any suggestions?