The BBC reports that a male swan (presumable guarding his nest) charged paddler Anthony Hensley's Kayak, capsized it and then sadly, Anthony drowned.
"They are not that strong and it's mostly show and bluster."
"They do fairly vigorously defend their little patch this time of year. Once the eggs are hatched he'll stay with the family and defend it.
"However, a large swan can give a thump, he says, and the best advice is to stay away from the nest, which is often a place along the bank or shore where the reeds are flattened and the female is sitting."
Closer to home? Watch out for hissing Canada Geese.