The peregrine falcon (Falco peregrinus) is a cosmopolitan bird of prey found almost everywhere on Earth except for extreme polar regions, very high mountains, and most tropical rainforests. The only major ice-free landmass from which it is entirely absent is New Zealand. This makes it the world’s most widespread raptor.
Physical Characteristics
Peregrine falcons are sexually dimorphic, with females being considerably larger than males. They can range in length from 34 to 58 cm and have a wingspan ranging from 74 to 120 cm. The back and wings of an adult peregrine falcon are typically bluish black to slate grey, while the underparts are white to rusty and barred with dark brown or black. They have a black head and “moustache” along the cheeks, which contrasts with the pale sides of the neck and white throat.
Peregrines have yellow ceres and feet, and black beaks and claws. The upper beak has a notch near the tip that enables them to sever the spinal column of their prey. Immature peregrine falcons are browner with streaked underparts, and have a pale bluish cere and orbital ring. One study shows that their black malar stripe helps reduce glare from solar radiation, allowing them to see better.
Speed and Hunting
Peregrine falcons are renowned for their speed, reaching over 320 km/h during their characteristic hunting stoop. This makes the peregrine falcon the fastest animal on the planet. The highest measured speed of a peregrine falcon is 389 km/h.
To hunt, the peregrine falcon soars to a great height and then dives steeply, striking one wing of its prey upon impact. Small bony tubercles on a falcon’s nostrils may guide the powerful airflow away from the nostrils, enabling the bird to breathe more easily while diving. To protect their eyes, peregrine falcons use their nictitating membranes to spread tears and clear debris from their eyes while maintaining vision.
Subspecies
Experts recognise 17 to 19 subspecies of Falco peregrinus, which vary in appearance and range. There is some disagreement about whether the Barbary falcon is a subspecies of Falco peregrinus or its own species. The Barbary falcon is generally paler than other peregrine falcons, has a red neck patch, and has a distinct way of flying. Some ornithologists consider the Barbary falcon a separate species because it breeds at different times of year than other peregrine falcon subspecies, even though they can interbreed.
Diet
The peregrine falcon’s diet consists almost exclusively of medium-sized birds. It will sometimes hunt small mammals, reptiles, or insects. Worldwide, an estimated 1,500 to 2,000 bird species are preyed upon by peregrine falcons. Peregrine falcons prefer to hunt at dawn and dusk, but they will also hunt nocturnally in cities, particularly during migration periods.
Reproduction
Peregrine falcons reach sexual maturity at one year of age and mate for life. They nest in a scrape, usually on cliff edges. In recent times, they have also been known to nest on tall human-made structures. The female chooses the nesting site and scrapes out a shallow hollow. Peregrine falcons do not add any nesting materials to the scrape.
Relationship with Humans
Peregrine falcons have been used in falconry for over 3,000 years. Peregrine falcons are well-respected in falconry for their strong hunting ability, high trainability, versatility, and availability via captive breeding. Captive-bred peregrine falcons are sometimes used at airports to scare birds away and reduce the risk of bird strikes.
Decline Due to Pesticides
The widespread use of pesticides, especially DDT, caused peregrine falcon populations to decline sharply in the mid-20th century. Biomagnification caused organochlorines to build up in the falcons’ tissues, thinning their eggshells and reducing the number of falcon eggs that survived until hatching.
Recovery Efforts
Following the ban on DDT in the early 1970s, peregrine falcon populations began to recover. Recovery efforts were aided by large-scale protection of nesting places and releases to the wild. Peregrine falcons were removed from the U.S. Endangered Species list in 1999. In the UK, peregrine falcon populations have also recovered thanks to conservation and protection work.
Cultural Significance
Peregrine falcons are often associated with aggression and martial prowess because of their hunting technique. In the late Middle Ages, the Western European nobility associated the peregrine falcon with princes. The peregrine falcon has served as a mascot for various organisations, appears on the 2007 U.S. Idaho state quarter, and is the official city bird of Chicago.
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