What bird is born with claws on its wing digits?

The Hoatzin is the bird that is born with claws on its wing digits. This unique feature is not seen in any other bird species. The claws are present in newborn Hoatzin chicks and are used to help them climb trees and navigate through their environment. However, as the bird grows and develops its flight feathers, the wing claws are eventually lost and become nonfunctional. This adaptation is believed to be an evolutionary remnant of a primitive trait seen in the ancestors of modern birds.