Why do baby birds have such large mouths?

Many nestlings have oversized mouths relative to their bodies because it helps them survive. A large gape makes it easier for parents to place food inside the chick’s mouth, especially in crowded nests. In some species, the bright colors of the mouth act as a visual signal that attracts feeding by adults. This is a practical adaptation to a life where chicks depend on rapid, repeated deliveries of food. The exaggerated mouth is not a flaw but a feeding tool.