Bird feet and legs

The anatomy of bird legs and feet is diverse, encompassing many accommodations to perform a wide variety of functions.

[3][4] Some of the lower bones of the foot (the distals and most of the metatarsal) are fused to form the tarsometatarsus – a third segment of the leg, specific to birds.

[5][6] The upper bones of the foot (proximals), in turn, are fused with the tibia to form the tibiotarsus, as over time the centralia disappeared.

Some lower bones of the foot are fused to form the tarsometatarsus – a third segment of the leg specific to birds.

[7] The foot's upper bones (proximals) are fused with the tibia to form the tibiotarsus, while the centralia are absent.

[5][6] The anterior (frontal) side of the dorsal end of the tibiotarsus (at the knee) contains a protruding enlargement called the cnemial crest.

[4] The bird knee joint between the femur and tibia (or rather tibiotarsus) points forwards, but is hidden within the feathers.

It is worth noting here that the name "thick knee" of the members of the family Burhinidae is a misnomer because their heels are large.

[2][8] The chicks in the orders Coraciiformes and Piciformes have ankles covered by a patch of tough skins with tubercles known as the heel-pad.

[8] 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,[7][10] which is specific to birds.

[2] Grebes and many other waterfowl have shorter femur and a more or less narrow pelvis, too, which gives the impression that their legs are attached to the rear as in loons.

[22] Some species (including nightjars, herons, frigatebirds, owls and pratincoles) have comb-like serrations on the claw of the middle toe that may aid in scratch preening.

[1] However, for cooling, this heat-exchange network can be bypassed and blood-flow through the foot significantly increased (giant petrels).

Some birds also excrete onto their feet, increasing heat loss via evaporation (storks, New World vultures).

African jacana . Extremely long toes [ 1 ] and claws help distribute the jacana's weight over a wide area to allow it to walk on floating leaves. [ 2 ]
Bird left leg and pelvic girdle skeleton
Chick of Pelargopsis capensis with heel-pads
The ostrich is the only bird that has the didactyl foot. [ 2 ]
Grey parrot grips the perch with zygodactyl feet.
Palmate feet – Chilean flamingo .
Totipalmate feet – blue-footed booby .
Western grebe presenting a lobate foot.
Lobate feet – a chick of the Eurasian coot .
The great crested grebe . The feet in loons [ 2 ] and grebes [ 2 ] [ 7 ] are placed far at the rear of the body - a powerful accommodation to swimming underwater, [ 7 ] but a handicap for walking.
The snowshoe -like foot of the willow ptarmigan is an adaptation for walking on snow. [ 1 ]
Toe arrangement in a bird's right foot
Webbing and lobation in a bird's right foot