As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Wednesday, 12 February 2020

Why are bird eggs in cold climates darker colored?

A global survey suggests that it might help keep them warmer

DEC 6, 2019 — 6:45 AM EST

Bird eggs come in a dizzying array of colors. But from a global perspective, that diversity follows a simple pattern, new research shows. The colder the climate, the darker the egg.
Darker eggs absorb more heat than lighter ones. This could help developing chicks stay warm while their parents forage for food. That’s the conclusion of the study. It appeared online October 28 in Nature Ecology and Evolution.

Biologists have long tried to understand why birds’ eggs come in so many shapes and colors. There could be many reasons. Color may help camouflage eggs from predators. Egg shape or color might also somehow protect eggs against bacteria or signal their quality. Shape or color might even help keep an egg warm. Scientists have turned up some evidence to support all of these hypotheses, says Phillip Wisocki. He worked on the research while studying biology at Long Island University Post in Brookville, N.Y.

Adds Daniel Hanley, scientists were never sure whether any of these factors were important to egg diversity. This biologist advised Wisocki on his research.

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