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Home Adaptations Feet Perching

Most small songbirds are also called perching birds or passerines.

Their feet are typically small and have no feathers.

Songbird feet have three toes pointed forward and one toe pointed backward. This toe arrangement is known as anisodactyl.

Songbirds have very little feeling in their feet because their feet have few nerves and blood vessels. This adaptation allows songbirds to land on cold perches such as wires when the weather is frosty.

When passerines roost (settle down to rest), their belly feathers cover their feet to keep them warm. If the weather is especially cold, many passerines will squat to cover their feet as they eat.

Maybe you've looked up at passerines on a wire and wondered how they can stay in place when they fall asleep. They're able to keep their grip because perching birds have thin tendons called flexor tendons that extend from the leg muscles down the back of the tarsus bone and attach to the toes.

When a bird lands on a perch, these flexor tendons tighten, causing the toes to lock around the perch. It's an involuntary reflex. The tendons stay tight until the legs straighten.

Black-capped Chickadee

  Black-capped Chickadee
(Courtesy NEBRASKAland

Baltimore oriole

  Baltimore Oriole
(Courtesy NEBRASKAland Magazine/NGPC)
American Robin

American Robin
(Courtesy NEBRASKAland Magazine/NGPC)

When the bird begins to stand up, its legs straighten, causing the tendons to relax and the toes to unlock. This releases the feet.

Falling asleep doesn't change the bird's grip because the weight of the bird keeps the leg in the locked position.

Now you know how a bird can fall asleep without falling off its perch!

Here's one more feat involving feet: in addition to using their feet to perch on branches and wires, passerines use their feet for feeding. For example, the chickadee will hold a sunflower seed with its foot and use its beak to crack it open.




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