Peregrine Falcon

Lore & Background

The peregrine falcon became an endangered species in many areas because of the widespread use of various pesticides, especially DDT. Since the ban on DDT from the early 1970s, populations have recovered, supported by large-scale protection of nesting places and releases to the wild. The peregrine is a highly successful example of urban wildlife in much of its range, taking advantage of tall buildings as nest sites, and an abundance of prey such as pigeons and ducks. Both the English and scientific names of the species mean 'wandering falcon', referring to the migratory habits of many northern populations.

In Their Own Story

The peregrine falcon was first described under its current binomial name by English ornithologist Marmaduke Tunstall in his 1771 work Ornithologia Britannica. The scientific name Falco peregrinus is a Medieval Latin phrase that was used by Albertus Magnus in 1225. Peregrinus is Latin, meaning 'one from abroad' or 'coming from foreign parts'. It is likely the name was used as juvenile birds were taken while journeying to their breeding location (rather than from the nest), as falcon nests are often difficult to get at. The Latin term for falcon, falco, is related to falx, meaning 'sickle', in reference to the silhouette of the falcon's long, pointed wings in flight.

Reader's Guide

The peregrine falcon has a body length of 34 to 58 cm (13–23 in) and a wingspan from 74 to 120 cm (29–47 in). Males weigh 330 to 1,000 g (12–35 oz) and the noticeably larger females weigh 700 to 1,500 g (25–53 oz). The back and the long pointed wings of the adult are usually bluish black to slate grey with indistinct darker barring; the wingtips are black. The white to rusty underparts are barred with thin clean bands of dark brown or black. The top of the head and a 'moustache' along the cheeks are black, contrasting sharply with the pale sides of the neck and white throat. The cere is yellow, as are the feet, and the beak and claws are black. The upper beak is notched near the tip, an adaptation which enables falcons to kill prey by severing the spinal column at the neck. An immature bird is much browner, with streaked, rather than barred, underparts.

Did You Know?

• The peregrine falcon is the world's most widespread raptor, found nearly everywhere on Earth except extreme polar regions, very high mountains, most tropical rainforests, and New Zealand.
• Females can be up to 30% larger than males, with some weighing about 50% more than their male breeding mates.
• The upper beak is notched near the tip, an adaptation that enables falcons to kill prey by severing the spinal column at the neck.
• A 2021 study concluded that the black malar stripe below the falcon's eyes serves to improve vision by reducing glare, and is larger in areas that receive more sunlight.
• The Barbary falcon is now treated as a subspecies of the peregrine falcon, with only about 0.6–0.8% genetic differentiation, indicating a divergence during the Last Ice Age.

Global Distribution and Urban Adaptation

The breeding range includes land regions from the Arctic tundra to the tropics. It can be found nearly everywhere on Earth, except extreme polar regions, very high mountains, and most tropical rainforests. The only major ice-free landmasses from which it is entirely absent are the islands of New Zealand, making it the world's most widespread raptor and one of the most widely found wild bird species. In fact, the only land-based bird species found over a larger geographic area, domestic and feral pigeons, owe their success to human-led introduction. Both are domesticated forms of the rock dove, and are a major prey species for peregrine populations. Due to their greater abundance in cities than most other birds, feral pigeons support many peregrine populations as a staple food source, especially in urban settings. The peregrine is a highly successful example of urban wildlife in much of its range, taking advantage of tall buildings as nest sites, and an abundance of prey such as pigeons and ducks.

Physical Characteristics and Sexual Dimorphism

The peregrine falcon has a body length of 34 to 58 cm (13–23 in) and a wingspan from 74 to 120 cm (29–47 in). The male and female have similar markings and plumage but, as with many birds of prey, the peregrine falcon displays marked sexual dimorphism in size, with the female measuring up to 30% larger than the male. Males weigh 330 to 1,000 g (12–35 oz) and the noticeably larger females weigh 700 to 1,500 g (25–53 oz). In most subspecies, males weigh less than 700 g (25 oz) and females weigh more than 800 g (28 oz), and cases of females weighing about 50% more than their male breeding mates are not uncommon. The back and the long pointed wings of the adult are usually bluish black to slate grey with indistinct darker barring; the wingtips are black. The white to rusty underparts are barred with thin clean bands of dark brown or black. The top of the head and a 'moustache' along the cheeks are black, contrasting sharply with the pale sides of the neck and white throat. The cere is yellow, as are the feet, and the beak and claws are black. The upper beak is notched near the tip, an adaptation which enables falcons to kill prey by severing the spinal column at the neck. A 2021 study of photos from around the world showed that the malar stripe is larger in areas that receive more sunlight, and concluded that the stripe serves to improve the falcon's vision by reducing glare.

Conservation History and Recovery

The peregrine falcon became an endangered species in many areas because of the widespread use of various pesticides, especially DDT. Since the ban on DDT from the early 1970s, populations have recovered, supported by large-scale protection of nesting places and releases to the wild.

Taxonomy, Evolution, and Falconry

Falco peregrinus was first described under its current binomial name by English ornithologist Marmaduke Tunstall in his 1771 work Ornithologia Britannica. The scientific name Falco peregrinus is a Medieval Latin phrase that was used by Albertus Magnus in 1225. Peregrinus is Latin, meaning 'one from abroad' or 'coming from foreign parts'. A total of 18 or 19 regional subspecies are accepted, which vary in appearance. Disagreement existed in the past over whether the distinctive Barbary falcon was represented by two subspecies of Falco peregrinus or was a separate species, F. pelegrinoides, and several of the other subspecies were originally described as species. However, the difference in their appearance is very small, as is their genetic difference, being only about 0.6–0.8% genetically differentiated. That indicates the divergence is relatively recent, occurring during the Last Ice Age, and all major ornithological authorities now treat the Barbary falcon as a subspecies. The peregrine falcon is a well-respected falconry bird due to its strong hunting ability, high trainability, versatility, and availability via captive breeding. It is effective on most game bird species, from small to large. It has also been used as a religious, royal, or national symbol across many eras and civilizations.