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Peregrine Falcon Facts

Scientific name: Falco peregrinus

The peregrine falcon is a slate gray, crow-size raptor that can reach speeds of up to 200 mph and nests only on the ledges of cliffs, bridges and tall buildings. Pesticide Raptor Syndrome had so negatively impacted the species that by the 1960s the peregrine falcon population dwindled almost to the point of extinction and the peregrine falcon won the dubious distinction of becoming one of the first birds listed as endangered. In recent years the bird has made a wonderful recovery, with 1,650 breeding pairs recorded in 1999, although the species remains on the Commonwealth’s Endangered and Threatened Species list. WPC’s Peregrine Recovery Program protects two of the few active nest sites in Pennsylvania and the only sites documented in western Pennsylvania.

A History of Decline

• Before the 1960s peregrine falcons were one of the most widespread birds in the world, nesting at more than 350 sites east of the Mississippi River, including 44 in Pennsylvania. But, long-lived pesticides such as DDT accumulated in falcon food chains, causing the “pesticide raptor syndrome.” Females were unable to produce a sufficient eggshell, resulting in the eggs cracking during incubation. Populations diminished by the 1960s, with no successful nestings east of the Mississippi River by 1965.

• Peregrine falcons are one of the first species listed as endangered under the U.S. Endangered Species Act of 1974.

• The Pennsylvania Game Commission is the official regulatory and management agency for this species in the Commonwealth.

• Dr. Thomas Cade of Cornell University began the first peregrine recovery program in 1970. Young birds were hatched from eggs in captivity and released into the wild. This program grew into The Peregrine Fund and the creation of the World Center for Birds of Prey in Boise, Idaho.

• Thanks to a growing resurgence in population, 1,650 peregrine breeding pairs were recorded in the United States and Canada in 1999, smashing the recovery goal of 631.

• Peregrine falcons were removed from the federal list of the Endangered and Threatened Species on August 20, 1999.

• The peregrine remains in part protected by the federal North American Migratory Bird Act.

Peregrines remain on the Commonwealth’s Endangered and Threatened Species list and will remain there until the Pennsylvania Game Commission determines that they have recovered in the state.

The Pittsburgh Connection

Pittsburgh's original pair of peregrines arrived in the winter of 1989 – 1990.   Both birds were less than one year old. They claimed the downtown area as their territory and regularly chased away hawks and vultures.

During the late 1990s, peregrines were observed in Oakland at the University of Pittsburgh.  A pair was frequenting the Cathedral of Learning and may have attempted nesting in a hidden spot without known success. 

As of 2002, two pairs of peregrines are known to nest in western Pennsylvania – both in the City of Pittsburgh.  The other known Pennsylvania nests are in the eastern portion of the Commonwealth.

Because peregrines are highly territorial during nesting, only one pair will reside in downtown Pittsburgh.  The second pair in Oakland is far enough away to establish a separate territory.  Both pairs are expected to reside in the city for years to come.

This year, a daughter of the Gulf Tower pair, hatched in 1999, is nesting at Cleveland’s Terminal Tower.  She won the site after a fierce battle with the resident male’s former mate.

The Gulf Tower Site

The original pair in Pittsburgh wore coded leg bands identifying them as part of the peregrine recovery program. The original female was identified as being released in the Shenandoah Mountains on the Virginia-West Virginia border in June 1989. The male was released in northeastern Tennessee in June 1989.

In 1998 the original female peregrine disappeared and an “unbanded” female took up residency and continues to nest at the Gulf Tower.  The new female peregrine was banded in 1998 along with her chicks.  Her origin will never be known.  The male of the present pair is believed to be the original bird.

The Gulf Tower is the first known building nest site in Pennsylvania; most others were on bridges. Buildings are generally more successful locations for peregrines when nesting in cities.

WPC selected the Gulf Tower from a number of buildings evaluated as potential nesting sites because of the positive attitude of the building management, and because it offered:

• one of the tallest locations in the city (at least 15 stories is best);
• a high, secluded ledge on the 37th floor with no expansive areas of reflective glass;
• access to the roof that can be controlled and is not necessary on a regular basis for building maintenance;
• a relatively safe first-flight environment for young; and
• cooperation by tenants on the 37th floor to take precautions in protecting the birds’ privacy.

A custom-made nest box is constructed of red cedar where wood is in contact with the birds, and of weather-resistant treated lumber elsewhere (cedar is also weather resistant).

The size of the box is: 57" long by 42.5" wide and 6" deep. A three-sided shelter (18" deep by 12" high) with a roof is located at one end.

The bottom of the box is filled with approximately 500 lbs. of “shot” size round gravel upon which the eggs are laid. Peregrines instinctively look for this or similar “substrate” in which to sculpt a depression so eggs can’t roll.

WPC volunteers Darrell Packer and Cliff Packer built the Gulf Tower nest box, with assistance by Rick Jenkins. Local builders donated the necessary materials.

Peregrines must be protected from human intrusion during nesting. At the Gulf Tower site, protection is provided by Gulf Tower Management and building tenants.  State and federal laws provide fines/imprisonment for disturbing birds and endangered species.

The project is a cooperative effort between the Gulf Tower, Western Pennsylvania Conservancy and the Pennsylvania Game Commission.

The University of Pittsburgh Site

The Oakland peregrines chose the Cathedral of Learning themselves and claimed it as their territory before any people became involved.  They prefer the Cathedral because it resembles their traditional cliff nesting sites.

The pair at the Cathedral of Learning wear coded leg bands, but the bands have not been read yet so neither bird’s origin has been identified.

The Cathedral of Learning nest site offers many advantages:

-- the positive and cooperative attitude of Pitt’s Facilities Management team;

-- the tallest location outside of downtown Pittsburgh (40 stories) with an adequate territorial buffer zone from the downtown pair;

-- a high, secluded ledge with no expansive areas of reflective glass;

-- controlled access to the roof and the ledge area;

-- a relatively safe first-flight environment for young.

A custom-made nest box is constructed of red cedar where wood is in contact with the birds, and of weather-resistant treated lumber elsewhere (cedar is also weather resistant).

The size of the box is: 36" long by 30" wide and 6" deep. A three-sided shelter (18" deep by 12" high) with a roof is located at one end.

The bottom of the box is filled with approximately 350 lbs. of “shot” size round gravel upon which the eggs are laid. Peregrines instinctively look for this or similar “substrate” in which to sculpt a depression so eggs can’t roll.

The Cathedral of Learning nest box was built by WPC staff member Charles Bier and volunteers Terry and Raven Bier, with assistance from WPC volunteer Kate St. John. Materials were paid for by the Pennsylvania Game Commission.

Peregrines must be protected from human intrusion during nesting. At the University of Pittsburgh, protection of the site is coordinated by Facilities Management.  State and federal laws provide fines/imprisonment for disturbing birds and endangered species.

The project is a cooperative effort between the University of Pittsburgh, Western Pennsylvania Conservancy and the Pennsylvania Game Commission.

Peregrine Profile

Average length, wingspread, and weight for the male and female peregrine falcons

                                                                                    Male                Female

                                    Length                                     14" - 16"         16" - 18"

                                    Wingspread                              37" - 39"         40" - 46"

                                    Weight                                     1-1.2 lbs.         1.6-2.1 lbs.

The average number of eggs/young produced for a healthy pair of peregrines is four.  The range is three to six.

Incubation of the eggs is accomplished largely by the female. The male provides food during the 31-day period.

Peregrine falcons feed almost exclusively on small-to-medium size birds caught in the air or occasionally on the ground. They will eat hundreds of species of birds, including city pigeons and waterfowl.

Few birds are as swift as the peregrine, who can dive after prey at approximately 200 mph.

Young peregrines are fed pieces of birds caught by adults.

Pigeon control programs that use certain poisons can be dangerous to peregrine falcons. Two peregrines died in Baltimore after eating poisoned pigeons.

Pennsylvania peregrine falcons are not migratory as adults and remain through the winter.

The young peregrines will be on their own a few weeks after fledging (leaving the nest) and are expected to disperse to areas outside of Pittsburgh by summer's end.

Click here to go back the peregrine banding site.