Birds' Flight Time Determines Egg Shape

[FAM Times reporter Jennylyn Gianan] It has been discovered that the amount of time birds spend flying determines the shape of their eggs.

Researchers at Princeton University in the United States collected photographs of some 49,000 eggs from different bird species and compared them with factors including the weight, nest type, and wing shape of each parent bird.

The comparative study identified the two factors with the greatest influence on egg shape: egg size and wing shape, or a measurement of how long and pointed a bird's wings are.

It is easy to understand that larger eggs may take on a different shape because they are subjected to greater pressure as they emerge from the mother's body.

However, scientists were surprised to discover that wing shape also affects egg shape.

This is because wing shape is a biological measure that indicates how powerfully a bird flies and how long it remains airborne.

Naturally, the longer a bird stays in the air, the more power it needs. For example, birds that flap their wings frequently lay slender, elongated, watermelon-shaped eggs, while owls, which flap less often, lay much rounder eggs.

The researchers compiled the data to test a theory that had quietly circulated since the early 1990s.

Birds with stronger wings have more efficiently developed bodies, allowing mothers to lay eggs more easily through narrow oviducts.

The researchers selected a biological model to test the forces exerted on eggs as they form inside the body and found that egg shape changes depending on the forces applied.

The comparative analysis of nearly 50,000 photographs alone provides compelling evidence, and the researchers said they would not stop there but would continue their research.

They added that further experiments are needed to prove that the biological model accurately reflects real-world conditions.

Jennylyn Gianan fam1@pcss.co.kr