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Peregrine Falcon (Falco peregrinus)



Peregrine Falcon (Falco peregrinus), listed as Endangered in Wisconsin, prefers relatively inaccessible rock ledges on the sides of steep bluffs and ledges on highrise buildings in urban areas. The required avoidance period is March 15 - July 10.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Peregrine Falcon (Falco peregrinus). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where occurrences of this species meet NHI data standards and is not meant as a comprehensive map of all observations.

Note: Species recently added to the NHI Working List may temporarily have blank occurrence maps.

Documented locations of Falco peregrinus in the Natural Heritage Inventory Database as of July 2015.
Summary Information
State StatusEND
Federal Status in Wisconsinnone
State RankS1S2B
Global RankG4
Tracked by NHIY

Species guidance

Identification: Peregrine falcons are sleek, crow-sized birds of prey, famous for their speed and beauty. For hundreds of years, peregrines have been prized for the sport of falconry. Recently, however, they have become well known as a species endangered due to pesticide contamination. These magnificent birds are now making a comeback in many parts of their former range.

The peregrine's black cap, black moustache below the eyes, white chin and buffy white under-parts barred with brown give it a striking appearance. It has dark brown eyes with yellow eye rings, a slate colored back and upper wings, a slate-blue beak and yellow feet and legs. Large, strong feet and a powerful, hooked beak enable the peregrine to carry and eat its prey. Peregrines are compact, fast birds with pointed wings.

As with most birds of prey, male peregrines are smaller than females. Male falcons are called tiercels, which means "one-third"; they are one-third smaller than females.

An immature peregrine falcon is similar to the adult, but has brown upperparts, a heavily streaked breast and a blue-gray beak, legs and feet.

Habitat: Peregrines nest mainly on high cliffs or bluffs, although some birds have taken up residence on ledges of skyscrapers or smoke stacks in large cities. High ledges near open water are preferred for nesting. The nest is a scrape, usually placed on open ledges, holes, or recesses of either igneous or sedimentary rock, or in loose soil, sand or vegetation, with no added nesting material, also, rarely in hollows of old trees 50-90 feet up.

State Distribution: Although peregrines can be seen in Wisconsin, most are birds migrating through the state between breeding sites in Canada and southern wintering grounds, following age-old migration routes along the Mississippi River and shore of the Great Lakes. Throughout Wisconsin they are rare summer visitors and rare winter visitors in south and central Wisconsin. In 1986, however, peregrines bred in Wisconsin for the first time in 22 years. Several of the adults were captive-bred birds that had been released in Minnesota. As many as three nesting attempts continued along the Mississippi River until 1989. Unfortunately, the young produced each year were killed by predators — great horned owls and/or raccoons. Breeding territories have been established in or near the cities of Milwaukee, Sheboygan, Madison, and La Crosse. Endangered Resources biologists were pleasantly surprised in 1988 when two one-year old peregrines occupied the release box as a nest site in Milwaukee. They produced two young — another surprise as they usually don't produce young until two years of age. The site has continued to be occupied since 1988 even though the individuals in the pair have changed. Twelve young (eight wild-produced, four captive-bred) have fledged from this nest. A pair of peregrines attempted to nest on the State Capitol Building in Madison in 1991. They ignored the nest box we provided and chose a very narrow ledge. At least one egg was found broken below the ledge. No young were produced at the site. Releases started in Milwaukee in 1987 with fourteen young. Thirty-three peregrines were released in Madison between 1988 and 1990. In 1991 La Crosse was the release site for 15 peregrines. Releases will continue for at least another year. More sightings of peregrines continue to be reported. Hopefully, more will come back to Wisconsin to nest.

Global Distribution: The Latin name "peregrinus" means "wandering" or "coming from foreign parts." Peregrine falcons are distributed worldwide, occurring on every continent except Antarctica. Some northern populations migrate long distances.

There are three subspecies of peregrines in North America. They differ slightly in appearance, breed in distinct regions and migrate different distances. Peale's peregrine (F. p. pealei) nests and winters along the coasts of Alaska and British Columbia. The tundra peregrine (F. p. tundrius) breeds in the Canadian arctic south to treeline and migrates as far south as Argentina. The subspecies F. p. anatum, native to North America south of treeline (including Wisconsin), tends to overwinter in the southern U.S., Central America and the Caribbean. This subspecies no longer exists east of the Mississippi.

Rationale for Species Listing and Threats: Between 1940 and 1960 these birds were found along the Wisconsin side of the Mississippi River, along the lower Wisconsin River, in Door County, and along the St. Croix River. At least 24 peregrine eyries were active in Wisconsin until the mid-1950s. Following World War II, however, this previously stable peregrine population began to decline. It took almost 20 years before reasons for the decline became clear. Evidence mounted that there was a direct connection between peregrine declines and the widespread use of pesticides like DDT. During this time, peregrines disappeared from Wisconsin and many other regions of the world.

By the late 1960s, research had begun to show that organochlorine pesticides like DDT caused physiological changes in peregrine falcons and other species of animals that fed high on the food chain. (Dr. Joseph Hickey at the University of Wisconsin-Madison coordinated several key meetings which addressed this problem.) Studies showed that pesticides became more highly concentrated with each link in the food chain (e.g., from plants, to plant-eating insects, to insect-eating birds, to bird-eating peregrine falcons).

Researchers found that high DDT concentrations caused a peregrine's liver to change the production of an enzyme essential to maintaining levels of the female sex hormone, estrogen. Estrogen levels declined, reducing the amount of calcium in the female's body and causing her to lay eggs with thin shells. When adults incubated the eggs, the eggs broke under their weight. In addition, parental behavior was influenced by the pesticides; even if the eggs hatched, adults often would not care for the chicks, which soon died. With few chicks surviving, peregrine populations dwindled. Of 300 pairs known to nest in the eastern U.S., none remained by the early 1970s.

Wisconsin banned the use of DDT in 1971; it was one of the first states to do so. In 1972, the federal government banned the use of DDT and other organochlorine pesticides in the U.S. However, residues still remain in the environment. Peregrines and other affected species have begun a slow recovery, but populations have yet to reach pre-pesticide numbers. In addition, these pesticides are still manufactured in the U.S. and sold for use in other countries. Many countries in Central and South America, where peregrine falcons overwinter, still use DDT. Thus, some falcons continue to be exposed to the pesticides and their adverse effects.

In some places, peregrines also have had to cope with habitat loss and human disturbance. For example, egg collecting was a popular hobby during the 1800s and peregrine eggs were gathered in large numbers; some chicks were taken from the nest for use by falconers; and peregrines were shot by owners of homing pigeons, who feared the falcons would kill their birds. However, pesticide contamination has by far been the main cause of peregrine declines.

Diet: Peregrine falcons eat small to medium-sized birds. They were formerly called "duck hawks" because they occasionally prey on ducks. Those living in urban areas eat large numbers of pigeons and starlings. Peregrines will eat a great variety of species, however, including flickers, robins, sparrows and meadowlarks depending on what is available.

Peregrines hunt primarily at dawn and dusk, when their prey is most active. They strike and capture birds in mid-air, a strategy that requires open space. Thus, they often hunt over open water, marshes, valleys, fields and tundras.

A peregrine hunts from the wing or from a high perch. It spots prey with keen eyes and begins its stoop, a streamlined dive with tail and wings folded and feet lying back. The falcon hits its prey with its foot, stunning or killing it, then swoops back around to catch it in mid-air. If the prey is too heavy to carry, the peregrine will let it fall to the ground and eat it there. Peregrines pluck their prey before eating it. Despite their reputation as able predators, peregrines often miss their strike and the prey escapes.

During a stoop, peregrines may reach speeds of 200 mph. The air pressure from this bullet-like plunge might burst an ordinary bird's lungs. It's thought that the series of baffles in a peregrine's nostrils slow the wind velocity, enabling the bird to breathe while diving.

Life and Natural History: Peregrines first breed at 1-3 years old. The male selects a nesting ledge and courts the female with aerobatics and a "wichew" call. The pair will return year after year to use the same nesting ledge, called an eyrie, which they defend from predators and other peregrines. Eyries are usually at least a mile apart. Lack of suitable nesting sites formerly limited the peregrine population. The same site may be used by successive pairs for many years. One ledge on an island off Wales has been used since at least 1243.

The female typically lays 4 creamy-white eggs with red-brown speckles anywhere from March to June. If the eggs are lost early in the nesting season, she may lay another clutch. The female does most of the incubating. After 28-32 days, the eggs hatch.

Newly hatched chicks are covered with creamy-white down and their feet are noticeably large. The male peregrine does most of the hunting, bringing food to the female and nestlings, which are called eyases. The eyases are fed by the female, who plucks feathers from the prey before giving it to them. The young fledge when 35-42 days old and remain with their parents for several weeks afterward. The adults capture prey for the fledglings, who learn to snatch it from them in mid-air. The young peregrines then begin to capture birds and large insects on their own.

On average, two eyases successfully fledge per nest. Infertile eggs and natural losses of eyases account for this success rate. If the birds survive their first year, their chances for survival are good. Some peregrines have been known to live 18-20 years, but the average lifespan is probably shorter (2-8 years).

Management Guidelines: In an effort to produce birds for falconry, falconers began breeding peregrines in captivity. Using techniques developed by falconers, biologists also began to breed them, with the hope of eventually reintroducing birds to the wild. Breeding programs at Cornell University and other places have been successful and many chicks have been reintroduced to traditional peregrine habitat.

Reintroduction involves more than just turning birds loose at a site. The birds are "hacked," a technique by which chicks are maintained (provided with food and shelter) at a release site until they are acclimated to it and old enough to fledge and hunt on their own. The hope is that the fledged birds will eventually return to the area and take up residence. Hacking, like rearing chicks in the wild, is not foolproof; some chicks have died, often due to predation by great horned owls and raccoons. But many states (e.g., New York, Massachusetts, New Jersey, Minnesota) have had great success. Peregrine falcons are nesting again in many places east of the Mississippi.

In 1976, University of Minnesota biologists brought five peregrine chicks from Cornell University to Wisconsin. The birds were hatched successfully at a traditional eyrie on the upper Mississippi River. None returned to breed in Wisconsin, however. Of three chicks hatched in 1977, two were killed by great horned owls who have been primarily responsible for impeding peregrine recruitment along the Mississippi River; the third was then returned to Cornell. In 1986, captive-bred peregrines, several hacked in Minnesota, bred in Wisconsin. The DNR's Bureau of Endangered Resources (BER) began releases of peregrines in Wisconsin in 1987.

The federal government has drafted a national peregrine falcon recovery plan and the BER is enacting a Peregrine Falcon Recovery Plan for Wisconsin. The BER's goal is to establish at least 10 breeding pairs of peregrines in the state by the year 2000, and eventually 18-24 pairs.The BER recovery plan calls for inventory and protection of existing and potential nesting habitat, and peregrine falcon protection through law enforcement, education and public information.



Peregrine Falcon

Photo © Laura Erickson.

Peregrine Falcon

Photo © Laura Erickson.

Peregrine Falcon

The Peregrine Falcon, formerly extirpated in Wisconsin, has been successfully reintroduced to portions of its former range, including the City of Milwaukee.

Photo © Laura Erickson.

Peregrine Falcon

Peregrine Falcon Chicks, Female.

Photo ©  USFWS.

Peregrine Falcon

Photo © A.B. Sheldon.

Wildlife Action Plan

Wisconsin Wildlife Action Plan graphic

Natural community (habitat) associations

The table below lists the natural communities that are associated with Peregrine Falcon. Only natural communities for which Peregrine Falcon is "high" (score=3) or "moderate" (score=2) associated are shown. See the key to association scores for complete definitions. Please see the Wildlife Action Plan to learn how this information was developed.

Natural community Score
Dry Cliff 3

Ecological landscape associations

The table below lists the ecological landscape association scores for Peregrine Falcon. The scores correspond to the map (3=High, 2=Moderate, 1=Low, 0=None). For more information, please see the Wildlife Action Plan.

This map shows the probability of Peregrine Falcon occurring in each of Wisconsin's Ecological Landscapes.  Actual scores can be found in the table to the left.

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Landscape-Community combinations of highest ecological priority*

Ecological priorities are the combinations of natural communities and ecological landscapes that provide Wisconsin's best opportunities to conserve important habitats for a given Species of Greatest Conservation Need. The 10 highest scoring combinations are considered ecological priorities and are listed below. More than 10 combinations are listed if multiple combinations tied for 10th place. For more information, please see the Wildlife Action Plan.

* Ecological priority score is a relative measure that is not meant for comparison between species. This score does not consider socio-economical factors that may dictate protection and/or management priorities differently than those determined solely by ecological analysis. Further, a low ecological priority score does not imply that management or preservation should not occur on a site if there are important reasons for doing so locally.

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Issues/threats and conservation actions

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.

Threats/issues and conservations actions for rare animals

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Last revised: Thursday, October 08, 2020