Bird eggs come in a variety of colors, sizes, and patterns. Have you ever wondered why? Scientists have been speculating about the reason for this for a long time and have come up with a few theories.
While we see many different colors of eggs, all of them stem from the same two pigments. Protoporphyrin is responsible for red/brown shades while Biliverdin is responsible for blue/green shades. All birds have access to both pigments, even if they only end up using one or neither of them.1
It’s thought that the color of the egg helps with:
Camouflage, for example, is usually seen with birds who have their nests on the ground. Their eggs may have a speckled appearance to blend in with rocks around them.1
Brood Parasitism is when another species puts its own eggs into another nest to fool that bird into caring for them. Specific patterns of eggs can help the owner of the nest identify its own eggs and not get roped into taking care of offspring that isn’t theirs.1
When it comes to temperature, scientists have found that in colder climates, birds tend to have eggs that are darker in color, while in warmer climates, birds tend to have eggs that are brighter in color. This is thought to help the embryos survive in their environment because darker shells can absorb more heat. Eggs can’t regulate their own temperatures, so their color helps keep them in the correct temperature range to keep the embryos safe.2
Check out more information about bird eggs in our article here. Learn more about what materials a bird will use for its nest and what all eggs have in common!