Anthony Hensley, 37 of Villa Park, worked for a company that uses swans to control Canada geese.
The accident happened in Des Plaines. Witnesses say Hensley was in a kayak and may have gotten too close to a swan's nest. They say a swan circled and attacked him.
It is not clear to the family how it could have happened.
"He was on the job; he was one of the people that controlled the geese at different sites," said Raymond Hensley, Anthony's father.
Raymond Hensley said that Anthony was an excellent swimmer. Anthony is survived by his wife and two daughters.