What foot structure characterizes the Order Piciformes, including toucans and barbets?

Zygodactylous feet, meaning two toes point forward and two point backward

The classification into the Order Piciformes is strongly associated with the presence of zygodactylous feet. This specific arrangement dictates that two toes face the front direction while the remaining two toes point backward. This configuration provides an exceptionally secure grip, which is biologically advantageous for clinging to and maneuvering on the vertical surfaces of tree trunks. This adaptation is crucial for survival and foraging techniques utilized by members of this order, such as woodpeckers, toucans, and barbets, allowing them to maintain purchase while drilling or bracing themselves during feeding activities, differentiating them functionally from birds whose feet are organized differently, such as those adapted for perching or terrestrial locomotion.