There are 19 regional variants (subspecies) of peregrine falcon worldwide. They vary considerably in size and color. Like all falcons, peregrine falcons have long, tapered wings and a slim, short tail. In North America they are roughly crow sized, ranging in length from between 36 and 49 cm in males and 45 to 58 cm in females. Wingspan varies from 91 to 112 cm. They weigh an average of 907 g. Like most birds of prey, female peregrine falcons are slightly larger than males. They are typically 15-20% larger and 40-50% heavier than males. Peregrine falcons have slate and blue-gray wings, black bars on their backs and pale underbellies. They have white faces with a black stripe on each cheek and large, dark eyes. Young birds tend to be darker and browner, with streaked, rather than barred, underparts. Plumage doesn't vary seasonally.

Average mass: 907 g.

Range length: 36 to 58 cm.

Range wingspan: 91 to 112 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: female larger

Average mass: 840 g.