Falcon birds are one of the 60 species of birds of prey that comprise of the family known as the Falconidae in the sequence of Falconiformes, which also has the eagles, hawks, kites and vultures included in the family. The real falcons are epitomized by a bullet-shaped body, which is normally long with pointed wings and a medium to sometimes long tail, with sharp long toes, hooked shaped claws, a short neck and a small hooked, normally jagged bill.

These birds vary in size from 15 to 63 cm (6 to 25 inches) in length and weigh up to 1.8 kg (4 lbs). Their colours may differ widely among the species; however both the sexes of any species normally look alike in appearance, except for the fact that the female falcon birds are larger in size.

Some of their species are also known as hobbies, kestrels, falconets, or the merlin (pigeon hawk); and nine or ten out of their species in four various groups are called the caracaras. In falconry, only the female peregrine (hawk/duck), Falco peregrinus, is appropriately called the falcon; in authoritarian falconry usage of the term, it might as well be applied to other birds on in an amalgamation with additional descriptive words. Likewise, the male peregrine is called a tiercel, but the can only be applied to various other male falcons with proper qualifying terms.

Falcon birds are very sturdy and swift fliers with immense aerial alertness. They hardly ever fly in a way of hawks. The peregrine has been timed at 290 km/h (180 mph). This rate of speed and alertness make falcon bird's unbeaten hunters of birds, reptiles, and many smaller mammals. Many of the species, conversely, are very insectivorous or eaters of carrion. But falcons wallop and seize their prey with their immensely sharp claws, and they normally kill their captured prey with their beaks.

These birds are usually private or they live in pairs. They make their nests on trees or on cliffs. They often invade the nests of other birds. The female falcon bird commonly lays two to six eggs, and both the male and the female falcons incubate their eggs and take care of their young. The falcon goes through four various yet unique periods in its life cycle. The duration of each period varies among the species and also with the size of the birds. The nestling period take the time from hatching to the first flight of the young one. During this time the young bird grows swiftly and grows all of its feathers. The post-nestling phase is of course the fledging. Through this time the parents of the young hunt food for their little ones. It is considered a juvenile when the bird leaves its nest to be on its own. The juvenile period lasts until the bird has reached its sexual maturity, which is when it is said to be an adult. Most falcons rarely ever live for more than 20 years.

The falcon birds' one real adversary and enemy is mankind. For many years the falcons were considered to be as vermin for they were thought to be a heavy toll on the livestock. However, now pesticides have been the main reason for devastating and jeopardizing several species. The first fossil record of the falcon family is from the Miocene Epoch of Argentina, which was present nearly 15 million years ago. Today, there are eleven known fossil species.