Hosts of avian brood parasites have evolved egg signatures with elevated information content.

Abstract in brief

• Hosts of brood parasitic birds have evolved egg signatures with higher information content to better distinguish their eggs from mimicry by parasites.
• In parasitized bird species, the diversity and unpredictability of egg traits are increased, mainly because these traits are less correlated within individual eggs, making each egg's unique signature more distinctive.
• This strategy allows host birds to enhance their defenses against parasitism by creating more complex and unpredictable egg signatures, rather than just increasing variation in individual traits.]