On Sunday five dead swans were found in the Dommelskanaal in Amsterdam.
The Dutch animal protection group Dierenbescherming found an exhausted adult female swan along with four dead cygets. The mother swan was very weak and had to be put down by a veterinarian.
According to Dierenbescherming, the cygnets drowned when trying to flee from a fast-moving boat.
A sixth swan, the father of the family, was picked up by an animal ambulance on Sunday night.