Minks are carnivorous predators and will hunt and kill ducklings for food. Ducklings are easy prey for minks because they are small and defenseless. Minks typically kill ducklings by biting them in the neck.
Competition for resources
Minks and ducks compete for the same resources, such as food and habitat. Minks may kill ducklings in order to reduce competition for these resources.
Protecting their territory
Minks are territorial animals and will defend their territory from other animals, including ducks. Minks may kill ducklings that enter their territory.