The most common digit arrangement is three in the front and one in the back as seen in perching birds and raptors like the Savanna Hawk (Figure 1). The difference between the perching food and the rap...The most common digit arrangement is three in the front and one in the back as seen in perching birds and raptors like the Savanna Hawk (Figure 1). The difference between the perching food and the raptor foot is not in the digit layout but in the claws. They can also have two in the front and two in the back as seen with the grasping bird in the image. Much of the development of various digit conformations is tied to the development of muscle formation and activation in the early stages.
