Syndactyl foot

Green Kingfisher
01-03-14 © J. Simón Tagtachian

Here we can see how peculiar the foot of this female green kingfisher is. Like the majority of birds it has three forward-pointing toes and a back-pointing one. But the three toes are not separated. The two external ones are fused at the base and then separate. It is called syndactyl foot and is typical of this family, the Alcidinidae.