When I see a bird that walks like a duck and swims like a duck and quacks like a duck, I call that bird a duck.

Don't quack like a duck, soar like an eagle.

If it looks like a duck, and quacks like a duck, we have at least to consider the possibility that we have a small aquatic bird of the family anatidae on our hands.

When I start a movie, the first day, I feel like a duck.

Be like a duck. Calm on the surface, but always paddling like the dickens underneath.

I can't say I hate cats, but holy cow, dogs are a horse of another color.