For some birds, recognising their own eggs can be a matter of life or death.
In a new study, scientists have shown that many birds affected by the parasitic Common Cuckoo - which lays its lethal offspring in other birds' nests - have evolved distinctive patterns on their eggs in order to distinguish them from those laid by a cuckoo cheat.
The study reveals that these signature patterns provide a powerful defense against cuckoo trickery, helping host birds to reject cuckoo eggs before they hatch and destroy the host's own brood.