Most of a bird’s leg is hidden in its body. The leg we see begins below the knee joint. The backward bend is actually an ankle joint and birds really walk on their toes. The bone between their “ankle” and their toes is the same as our foot arch but it looks like a shin bone. Animals which walk on their toes are called digitigrade animals. Most birds have three or four toes but these toes can be arranged in different ways.
Some species of chicken have a fifth toe which has evolved into a spur at the back, which never touches the ground and is used for self defense.
Ostrich are the only bird with just two toes. The bigger toe has a thick, hard nail and the smaller one has no nail. To see an ostrich in NZ you could visit an ostrich farm.
Feet for swimming
Birds have evolved ways to improve their ability to swim. Their feet are webbed. Birds are not the only animals to have webbed toes. Beavers and frogs are two examples of animals with this trait.
When birds swim they open their toes wide so that they can push against the water with more force and close them when bringing the foot forward for the next stroke. Sometimes they lift a foot at the end of a push stroke. This seems to give them more speed.
Webbed feet are not best suited for dry ground, that’s why ducks look awkward on land.They may look ungainly but they have a really cool heat exchange system in their legs and feet which stops their feet from freezing. Some other birds have this too.
There are several types of webbed feet.
Palmate (3 toes are webbed). Ducks and gulls have palmate feet.
Totipalmate (4 toes are webbed).
Gannets, shags and pelicans have totipalmate feet.
Semipalmate (front toes are partly webbed).
Sandpipers, plovers and some chickens have semipalmate feet. This helps birds who only occasionally go swimming and those who walk around on soft ground.
Coots and grebes are water birds but they do not have webbed feet. They have lobate toes which look a bit different from other birds’ toes. This is another paddling strategy. The front toes have flaps of skin, lobes, that open or close depending on which direction the foot is moving. It also helps support the bird on soft, marshy ground like wetlands and muddy pond edges.
Feet for catching prey
Owls, hawks, eagles and falcons swoop down and catch their prey in their feet. They have strong, curved, very sharp claws called talons for this. They can also use these talons for self defense and against anything which theatens them.
Feet for scratching and digging
Birds which use their feet to dig for worms and grubs often have four, long, skinny toes with sharp claws.
Feet for perching – 3 toes in front and 1 behind.
Most bird species are passerine (perching and song birds). They are usually small birds that nest off the ground in trees and shrubs. Their legs vary from thin to sturdy depending on how big a bird they are and how they find their food. Insect eaters have delecate legs while birds that hunt for grubs in leaf litter and run along the ground have stronger looking legs.
Feet for wading
Waders need long, slender legs to keep their body out of the water and long toes to spread their weight and give stability against rips and tidal flow. The longer their legs the deeper they can hunt. These birds tend to be patient hunters, pausing for long periods to lull fish into coming within striking distance. They move with slow and careful steps. Found in fresh water and salt water habitats: boggy areas, wetlands, estuaries and tidal river mouths. You can usually spot them in shallow water stalking small, aquatic prey. Herons, spoonbills, oystercatchers, pied stilts and godwits are all wading birds.
Feet for climbing – 2 toes in front and 2 behind.
This is called zygodactyl. Parrots can hold food in one foot and the branch in the other.
Feet for fighting and running
Thick, stout legs with two or three thick toes facing forward. The toes give stability to the bird as it runs.