The structure and color of birds’ legs is extremely variable. Everyone knows the difference between the webbed foot of a duck and the unwebbed toes of a chicken, and we can tell the thick, yellow toes of a chicken from the delicate black toes of a flycatcher. Often overlooked, however, is the fact that we can tell most small songbirds apart by their legs and feet – vireos from warblers from flycatchers from sparrows.
The quiz here introduces this idea with legs and feet of three different species of birds. In the answers you only have to identify the bird to family. The legs and feet of other species in each family are generally similar.
With thanks, again, to Brian E. Small for providing the beautiful photos. You can see lots more at his website.