Colorful Eggspression

Which came first – the white egg or the brown egg?

This is Sandra Tsing Loh with the Loh Down on Science.

There’s a reason we wear white after Memorial Day! Dressing in lighter colors helps keep us cool. Bird eggs do the same thing. Light-colored shells keep the embryo cool — but there’s a catch. Predators are more likely to see – and EAT! — lighter eggs. Which shade is better?

Phillip Wisocki from Long Island University Post and colleagues tried to UNSCRAMBLE the mystery. They scoured museums to collect over five THOUSAND eggs from hundreds of bird species. The team examined the brightness of each egg and mapped it using the birds’ breeding range.

Results? In cold regions like the arctic, birds lay darker eggs, as expected. It keeps the eggs warm and hides them from predators. Win-win! But in warmer regions like the tropics, eggs are brighter. EVEN if predators prowl nearby. Keeping cool outweighs hiding!

So, that EGG-splains why bird eggs come in so many colors!