Sometimes when I go birding I see several different species of birds standing on one leg and not two. Most of the time the birds are marsh/water dwellers such as Willets, Black-necked Stilts, Flamingos, and Wood Storks.
The most common and logical explanation to this bird habit is that birds sometimes stand on one leg to conserve heat.
Compared to the rest of the bird, the legs lose heat the fastest; and by having one leg in their feathers, the bird can conserve heat.
Why do some birds do this will others don’t?
Research shows that the colder the temperature a bird is in, the more likely that they are going to stand on one leg rather than two.
Animals and humans generally lose more heat while they are in the water than when they are on land.
This leads to the conclusion that birds that are frequently in the water (i.e. Willets and Wood Storks) will stand on more leg more often than birds that spend the majority of their time on land (i.e. Woodpeckers and Warblers).
What birds have you seen that stand on one leg?