Owls and ospreys have one toe – the fourth digit – that faces backward while perching but can swing to the side, forming a wider gripping surface to pluck prey out of air or water. Peregrine falcons use their disproportionately large feet like fists, striking their prey in midair, then catching it as it falls. Some hawks, including Cooper’s hawks and sharp-shinned hawks, have very long legs, allowing them to hold their prey away from them – so a seized bird can’t peck at its captor’s face. “A lot of hawks kill their prey by grabbing it and putting the back toe up through the animal into the heart.” And they have big, pointy toenails,” said McGowan. In the winter, grouse grow fringe-like projections along the front-facing digits to create something like a snowshoe. Ruffed grouse feet also create buoyancy – in snow, rather than sand. Other water birds, like plovers and herons that spend time standing on soft surfaces like sand and mud, have partially webbed, or semipalmate, feet there is a bit of webbing closest to where the digits connect to help distribute the birds’ weight and prevent them from sinking as they wade or run along the sand. Like the lobed-toed grebes, cormorants can compress their feet to reduce water resistance during the forward stroke. Other swimmers, like cormorants, have totipalmate feet, where digit 1 is slightly sideways, and there is webbing between each toe.
#Birds with webbed feet full
“They solved the same problem, but in a different way.”ĭuck and goose feet are palmately webbed, meaning there is full webbing between the front three toes, but the back toe is not webbed. “They have almost as much surface area as a fully-webbed foot,” McGowan said. These lobes spread out as the grebes paddle – or dive – through the water, then contract as the foot moves forward, creating a more streamlined effect. This includes members of the grebe family, whose front three toes are lobed rather than webbed. While most swimmers – including ducks, geese, loons, and gulls – have fully webbed feet, a few do not. “It’s simply a matter of variations in evolution to serve a similar function,” McGowan said. Woodpeckers don’t necessarily need both backward-facing toes, however, and some species – including the black-backed woodpecker and the aptly named American three-toed woodpecker – have only three toes: two forward and one back. The backward-facing toes can rotate sideways to gain a more stable purchase on a tree trunk. The two forward-facing toes help them climb and cling to trees. Woodpeckers generally have two toes facing forward and two backward in what is called a zygodactyl arrangement. There are webbed feet and lobed feet and powerfully sharp talons. A few have only three toes, or a digit 1 that has shrunken to the point of disuse. Some other birds have two toes forward and two back. Songbirds have what McGowan called “generalized all-purpose bird feet.” This group has the most common avian foot arrangement: digit 1 (which McGowan likened to a human thumb) faces backwards digits 2, 3, and 4 face forward. The feet consist mainly of bones and tendons, with very little muscle and few blood vessels. The backward-bending joint we may consider a knee is actually the birds’ ankle. From that, they’ve evolved in a number of different ways for various reasons.”īirds walk on those toes – not the entire foot. “All the birds basically started off with three toes forward, one back. “When you look at the foot of a bird, they’re not all the same,” said Kevin McGowan of the Cornell Lab of Ornithology. Rarely have I considered feet in my casual observations, although this part of a bird’s anatomy can be highly specialized for various uses. I look through binoculars at their feathers, the color variations along head and chest, the size of their beaks, the shape of their wings, and the tilt of their tails in my flailing attempts to distinguish one species from another. As spring’s crescendo of birdsong mellows now to a steadier summer trill, I listen for melodies I don’t recognize and try to figure out which birds are singing.
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