Falcons are swift raptors with long, pointed wings and long tails. They capture their primarily avian prey in open country by virtue of superior speed, either in powered flight or in a characteristic dive called a stoop. A stooping falcon folds its wings and dives from a high perch or while flying overhead, and may exceed 320 kilometers per hour (200 miles per hour). At such speeds, falcons must exercise precise control, exact timing, and superior coordination to strike and capture prey without harming themselves. Falcons typically seize prey in their strong, taloned feet, but are known to disable or even kill prey with sharp blows from their feet as they stoop on quarry. Prolonged ground fights with struggling prey animals could damage their relatively stiff flight feathers and reduce the future ability to catch prey, so falcons typically sever prey animals spinal cords by separating neck vertebrae to quickly end contests. Small notches near the tips of their beaks facilitate this behavior. Aside from the characteristic notched beaks, falcons have small bony protuberances in their nostrils to baffle airflow in stoops, allowing them to breathe at high speeds. Falcons have dark eyes and varying degrees of mustache-like facial patterns.
Falcons are typically dark gray or brown above, with lighter or even white plumage below, their underparts extensively marked with black or gray. Plumage of immature falcons mirrors adult patterns, but in shades of brown or gray (kestrels are rufous); underparts are typically streaked with brown or gray. Showing a strong degree of the sexual size dimorphism commonly seen in other raptors, females are up to 40% larger than males. Falcons do not build nests. Gyrfalcons and peregrines commonly deposit eggs directly on a scrape, or cleared space on ledges of rocky hillsides or mountain cliffs, but have been known to reoccupy disused raven, rough-legged hawk, and golden eagle nests. Merlins use old magpie nests or lay eggs on the ground under protective subalpine vegetation. Kestrels nest in old woodpecker holes, hollows in tree snags, and artificial nest boxes.
Falcons form monogamous pair bonds amidst courtship behavior including high-speed flight displays where male falcons soar, race, and dive over potential nest sites, and males ritually bringing prey to females, sometimes in aerobatic, air-to-air transfers. Incubation of eggs is often shared, but undertaken primarily by females. Males provide food for females and young nestlings; both sexes hunt when nestlings grow larger. Both sexes defend the nest, although females are typically more aggressive, screaming and diving at intruders.Caracaras are medium-sided new world raptors strongly related to the falcons. Contrary to their counterparts caracaras are slow-flying scavengers. They consist of about 10 species, all found in South America, Central America and the Caribbean. Together with the Falcons the form the newly formed order of the falconiformes. Today about a fouth of all falcons is under threat. These birds are especially hunted for trade and trapped to protect human interest, usually small game and birds.