Scientists know why birds' eggs are different shapes – round, potato-shaped and pointy. People once believed rounder eggs contained male chicks, but that was wrong. A new study says that the shape makes the bird fly better. A professor said birds have changed to lay eggs that have different shapes. They are all different in shape – everything from a round owl's egg to a pointy sandpiper egg.

The scientists put information about 50,000 eggs from 1,400 different bird species into a computer. They looked at the shape, length and height of the eggs. They also looked at how oval the eggs were. Birds with the most-oval-shaped eggs were the best fliers. The team was shocked to find that egg shape affected how well birds fly. Hummingbirds have the most-oval-shaped eggs; owls have the roundest eggs; and sea birds have the pointiest eggs.