Birds better at flying lay ‘pointy’ eggs – scientists say they’ve cracked the case...

A BIRD’S flying ability helps determine the shape of its eggs, according to the surprise findings of a new study.

The best fliers tend to lay eggs that are more “pointy” or elliptical, rather than rounded, researchers discovered.

Egg shape and powered flight may have evolved together because of the need to keep an airborne body sleek and streamlined, thereby reducing the size of the abdominal cavity. This caused a packaging problem because an egg still has to contain enough volume for healthy chick development.

Nature squared the circle by designing eggs that maximised internal volume without increasing their width, the experts believe. Dr Joseph Tobias, a member of the team from Imperial College London, said: “Variation across species in the size and shape of their eggs is not simply random but is instead related to differences in ecology, particularly the extent to which each species is designed for strong and streamlined flight.”

A wide range of theories has been put forward to explain the huge variation in the shape of birds’ eggs.

One proposal was that cliffnesting birds lay more coneshaped eggs which roll around in a tight circle and are less likely to tumble off the cliff edge.

Another idea suggests that egg shape is determined by incubation efficiency in a clutch.

To crack the egg mystery, the scientists studied eggs from 1,400 species, two of which were extinct.