Wildlife

Peregrine Falcon

Both the common and scientific name for the peregrine falcon means "wandering falcon", a reference to the migratory habits of many northern populations of these birds. It is the world's most widespread raptor and one of the most broadly distributed bird species on the planet. It can be found nearly everywhere on Earth; the only major ice-free landmass where it is entirely absent is New Zealand. Experts recognize 17 to 19 subspecies which vary in appearance. Three of these subspecies are found in North America.

Peregrine Falcon Description

The male and female have similar markings and plumage, but as in 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 average 2.5 lbs.; females 3.5 lbs.), it’s not uncommon for females to weigh 50% more than their mates. The back and long pointed wings of the adult are usually bluish black to slate grey with indistinct darker barring. The white to rusty underparts are barred with distinct thin bands of dark brown or black. The tail is long and narrow, light at the tip, and otherwise colored like the back,  but with thin crisp bars. The top of the head is dark with thick black “sideburns” covering  the cheeks that contrast sharply with the pale sides of the neck and white throat. The cere (skin around the eyes and beak) is yellow, as are the feet.  The beak and claws are black. Juveniles are much browner, heavily marked, and have vertical streaks instead of horizontal bars on the breast.

Take a look at the peregrine cam

Habitat

Peregrine falcons habitat generalists, they can be found from urban settings to tropics and deserts to tundra.  They have the most extensive natural distribution of any bird in the world, limited only by high elevations, extreme heat or cold. It is found on every continent except Antarctica. Peregrines can be seen all over North America, but they are more common along coasts. The hunting behavior of the peregrine is best suited to open or partially wooded habitats. Peregrine falcons often frequent cliffs and steep canyon walls. In urban areas these falcons can be seen perching or nesting on skyscrapers, water towers, power pylons, and other tall structures.

In Arizona, breeding sites may be found in a broad range of vegetation types from wetlands, riparian areas, and montane coniferous forests to Mohave and Sonoran Desert scrub. In regions with mild winters, it is usually a permanent resident, and some individuals, especially adult males, will remain on the breeding territory throughout the year.

Life Span and Reproduction

Peregrine falcons have been known to live up to 15 years in the wild. They have few enemies, humans are chief among them.  Apart from shooting and collision with human-made objects, the peregrine falcon suffered greatly from DDT poisoning that weakened egg shells and nearly drove these birds to extinction.  Peregrines may also be killed by larger hawks, owls and eagles and predators such as raccoons and great-horned owls occasionally take eggs or chicks from the nests. 

The peregrine falcon reaches sexually maturity at one to three years of age, breeding at two years of age in healthy populations. Peregrines mate for life and returns to the same nesting spot annually. The courtship flight includes a mix of aerial acrobatics, precise spirals, and steep dives. The male passes prey it has caught to the female in mid-air. During this prey handoff the female actually flies upside-down to receive the food from the male's talons.

The peregrine falcon nests on remote ledges of cliffs or canyon walls where many predators cannot go. The female prepares the nest site by making a shallow scrape in the loose soil, sand, gravel, or dead vegetation in which to lay eggs. No nest materials are added. Cliff nests are generally located under an overhang or on ledges with vegetation. In many parts of the world peregrine falcons have adapted to urban habitats, nesting on skyscraper window ledges and other lofty situations. Here they find situations that mimic those found in nature. In many urban area the presence of peregrines is encouraged, by constructions of nest boxes and sometimes draw media attention and often are monitored by cameras (such as this site).

In the Northern Hemisphere eggs are laid from February to March. If for some reason the eggs are lost or destroyed early in the nesting season, the female usually lays another clutch. Generally three to four eggs, but sometimes as few as one or as many as five, are laid in the scrape. The eggs are incubated for 29 to 33 days, mainly by the female.  The male also helps with the incubation of the eggs during the day, but only the female incubating them at night.

At hatching, the chicks are covered with creamy-white down and have disproportionately large feet. The male and the female both leave the nest to gather prey to feed the young. The hunting territory of the parents may extend to a radius of 12 to 15 mi from the nest site. Chicks fledge 42 to 46 days after hatching but remain dependent on their parents for up to two months.  Mortality in the first year is about 60%, declining to around 30% annually in adults.

Feeding and Behavior

The peregrine falcon has the most diverse avian prey of any raptor in North America. Peregrine falcons catch their prey in the air with swift, spectacular dives, called stoops. The peregrine falcon is often considered the fastest animal on the planet and may reach speed in excess of 200 miles per hour when performing a stoop.  Avian prey is knocked from the air by the falcon hitting one wing of its prey so as not to harm itself on impact at these great speeds.

This falcon feeds almost exclusively on medium-sized birds such as pigeons and doves, waterfowl, songbirds, and wading birds. Smaller hawks and owls (mainly smaller falcons such as the American kestrel, merlin and sharp-shinned hawks) are also regularly taken. Historic accounts often refer to peregrines as “duck hawks”. In cities they are masterful at catching pigeons; the main component of the urban peregrine's diet. A variety of other common urban birds are also taken including mourning doves, common swifts, northern flickers, common starlings, common blackbirds, and corvids (crows, jays, etc.). The peregrines on occasion will take small mammals such as rats, voles, hares, shrews, mice and squirrels. Bats are taken in flight at dusk. Other items such as insects and reptiles make up a small proportion of the diet.

The peregrine falcon hunts most often at dawn and dusk, when prey is most active, but also nocturnally in cities, particularly during migration periods when many species of birds are traveling to wintering or nesting grounds. The peregrine requires open space in order to hunt, and therefore often hunts over open water, marshes, valleys, and fields, searching for prey from high perches or from the air. Congregations of migrating fowl, especially species that gather in the open like shorebirds, can be quite attractive to hunting peregrines. Once prey is spotted, the peregrine begins its stoop, folding back the tail and wings, with feet tucked close to its body. Prey is typically struck and captured in mid-air; the peregrine falcon strikes its prey with its feet clenched, stunning or killing it with the impact, then turns to catch the prey in mid-air. If its prey is too heavy to carry, a peregrine will drop it to the ground and eat it there. If they miss the initial strike, peregrines will chase their prey. The upper beak is notched near the tip, an adaptation for dispatching captured prey that is still alive.

Relationship with Humans

Use in falconry

The peregrine falcon is a highly prized hunting bird, and has been used in falconry for more than 3,000 years, beginning with nomads in central Asia. It is renowned for its speed, eagerness to hunt, and easiness to train.  The peregrine falcon naturally circles its hunting area so flushed game is easily spotted.  This leads to an exciting high speed diving stoop to take the quarry.

Trained peregrine falcons are also occasionally used to scare away birds at airports to reduce the risk of bird-plane strikes, improving air-traffic safety, and are often used to deter urban pigeons and starlings in city settings.

Current status

Peregrine falcons were virtually eradicated from eastern North America by pesticide poisoning in the middle 20th century. After significant recovery efforts, peregrine recovery efforts have been remarkably successful. The widespread restriction of DDT use eventually allowed released birds to breed successfully. Peregrine falcons were removed from the United States' endangered species list in 1999. The successful recovery program was aided by the effort and knowledge of falconers – in collaboration with The Peregrine Fund and state and federal wildlife agencies  Peregrines now breed in many mountainous and coastal areas, and nest in some urban areas, capitalizing on the urban feral pigeon populations for food. Arizona has one of the most robust populations of peregrines in the United States.

Where to See Peregrine Falcons

The falcons on this camera are nesting on the county building in downtown Phoenix, Maricopa County, Arizona.  They perch on communication towers and other good vantage points in the greater Phoenix area and may be seen perched on window ledges or soaring among the tall buildings anytime of the year. Peregrines may also be observed nearly anywhere in the state, particularly in precipitous terrain from the Grand Canyon and central Arizona lakes to the international border.