Birds are generally digitigrade animals (toe-walkers), which affects the structure of their leg skeleton. They use only … See more

The legs are attached to a very strong, lightweight assembly consisting of the pelvic girdle extensively fused with the uniform spinal bone called the synsacrum, which is specific to birds. The synsacrum is built from the … See more

Fusions of individual bones into strong, rigid structures are characteristic.
Most major bird bones are extensively pneumatized. They contain many air pockets connected to the pulmonary air sacs of … See more

Most birds, except loons and grebes, are digitigrade, not plantigrade. Also, chicks in the nest can use the entire foot (toes and tarsometatarsus) with the heel on the ground.
Loons ten… See more

Typical toe arrangements in birds are:
• Anisodactyl: three toes in front (2, 3, 4), and one in back (1); in nearly all songbirds and most other perching birds.
• Zygodactyl: two toes in front (2, 3) and two in back (1, 4) – the out… See more

All birds have claws at the end of the toes. The claws are typically curved and the radius of curvature tends to be greater as the bird is larger although they tend to be straighter in large ground dwelling birds such as rati… See more