Bird eggs laid in cold climates are darker, which may keep eggs warm
A global survey of bird egg color reveals a simple trend: the colder the climate, the darker the egg
![bird eggs](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2019/10/102519_jl_birdegg_feat.jpg?fit=1028%2C579&ssl=1)
Bird eggs come in a wide variety of shapes, sizes and colors. A new global study suggests that northern birds in colder climates tend to have darker eggs.
Frans Lanting/MINT Images/Science Source