For decades, a debate about why birds' eggs are speckled has focused on two possible explanations:

• Explanation 1. Speckles provide camouflage. This explanation maintains that speckled eggs blend into their surroundings and thereby reduce the chance predators will spot them.
• Explanation 2. Speckles provide a way for adults to differentiate between eggs in the nest. This explanation suggests that the speckles help parent birds identify eggs and keep track of which eggs they have warmed or turned in the nest.

But now a new explanation has emerged, one that suggests the speckling pattern on birds' eggs helps strengthen the egg shell.

Find out more: Speckles Make Bird Eggs Stronger, Study Finds (National Geographic)

Photo © Susan Drew