Here, a floating bird is installed. Try rotating, pushing or pulling it.

What did you observe? 
The bird floats without falling down. It is very stable

The science behind it :
The floating bird has its centre of gravity located at the tip of the beak. The centre of gravity (also called the centre of mass) is the point at which the mass of the body is perfectly balanced. The bird is perfectly balanced at the beak location. It is because the bird is designed this way. The wings are extended in front of the beak far enough, and made heavy enough, to balance the weight of the bird behind the beak.