like a duck takes to water

• as a duck takes to water
• like a duck to water

Note: These are full verb forms.

• take to something like a duck to water
• take to something like a duck takes to water
• take to something as a duck takes to water

like a duck takes to water

1. (simile, idiomatic) Very naturally; without effort.

   She started skating and learned quickly, like a duck takes to water.

• like a knife through butter

• like water off a duck's back