Conserve Wildlife Blog

Month of the Falcon – Part II

January 8th, 2014


by Ben Wurst, Habitat Program Manager

Peregrines are now common residents of NJ's coast. Photo by Northside Jim.

Peregrines are now common residents of NJ’s coast. Photo by Northside Jim.

It’s hard to believe now, but peregrine falcons were once extirpated from their nesting grounds in the Eastern United States. They were federally listed as endangered in 1969 (prior to the passage of the Endangered Species Act of 1973) under the Endangered Species Conservation Act of 1969.

Shortly thereafter a reintroduction project began. New Jersey was one of the first places were wild nesting occurred.

Today more than 25 pairs of peregrines nest in New Jersey and their reproduction here remains strong. However, biologists remain concerned of their long term recovery since they have some of the highest loads of DDE and mercury (Clark et al. 2009).

The Sad Decline of the Peregrine Falcon

Peregrines were once extirpated from all nesting grounds that were east of the Mississippi River by 1964. Prior to their extirpation there was estimated to have been 350 pairs that nested in the East. In New Jersey they formally nested on rock cliffs and outcrops on the Delaware River and along the banks of the Hudson River on the Palisades.

The biggest factor in their decline was the persistent organochloride pesticide, DDT (dichlorodiphenyltrichloroethane) which was heavily used in New Jersey to control biting insects in the 1950s.

DDT was a fat soluble pesticide and was bio-magnified in the food chain and peregrines, being top tier predators, accumulated huge loads of the containment. DDT inhibited the production of calcium and subsequently egg shells were too thin to support the weight of an incubating adult.  After Rachel Carson wrote about the environment impact of DDT in her book, Silent Spring, the largest environmental movement began and DDT was banned in New Jersey in 1968 and federally in 1972.

An Inspirational Recovery Takes Flight
Eggs taken from bridge for incubation. Courtesy NJDFW.

Eggs taken from bridge for incubation. Courtesy NJDFW.

The initial recovery of peregrines began in the early 1970s when an artificial breeding program started at Cornell University by Tom J. Cade and many other dedicated raptor biologists. The program encompassed collecting wild and captive birds to create a captive breeding program in a pole barn that was dubbed the “Peregrine Palace” at Cornell.

In the early days it was difficult work, which was mainly from the lack of funding for such work. Many conservation groups were not in favor since they did not agree with the work being done mostly by falconers. Things changed quickly once the National Audubon Society endorsed the work. Donations from private individuals and corporations began to come in and put into a fund, called the “Peregrine Fund.”

It was then that the non-profit “The Peregrine Fund, Inc.” was founded. The passing of the most important legislation, the Endangered Species Act of 1973, helped to direct conservation efforts to the peregrine reintroduction project and in 1975 many states began to get involved.

Reintroducing the Falcon to New Jersey Skies
Building a hack-nest tower in New Jersey. Courtesy NJDFW

Building a hack-nest tower in New Jersey. Courtesy NJDFW

The recovery of peregrines was not high on the federal government’s priority list for funding. Other species like the red wolf, Bald eagle, and American alligator were given priority. Tom Cade ended up spearheading a unique partnership with colleagues in the U.S. Army to fund the release of peregrines at the Edgewood Arsenal and Aberdeen Proving Grounds in Maryland. The hacking project got underway and New Jersey was the first state in the east to take part in the new program.

At the time Pete McLain was the Deputy Chief of NJ Division of Fish and he forged a partnership with Tom Cade of Cornell to start a reintroduction program for peregrine falcons here in New Jersey. Pete was an asset to the reintroduction efforts. Among other things, he showed Peregrine Fund staff how to properly build a hacking tower on the coastal saltmarsh (without it sinking).

Between 1975 and 1980 a total of 55 young birds were released at hacking towers throughout the state. Hacking is a falconer’s term used to describe the process of placing captive bred birds in boxes that are meant to mimic a natural nest site. The boxes provide shelter and protection from predators, and the birds are provided with food as they learn to fly and hunt prey.

This “soft release” is a way for them to imprint on their natural surroundings and not on humans that helped to raise them. The hope is that the young birds return after reaching adulthood to breed and occupy local territories.

The Return of a Magnificent Raptor!

In 1978 the first pair of peregrines returned to New Jersey. The first wild nesting of them, since their extirpation in the early 1960s, occurred in 1980 at Edwin B. Forsythe NWR in Oceanville. Hacking continued from 1975-1980.

Young peregrine in hack cage. Courtesy NJDFW

Young peregrine in hack cage. Courtesy NJDFW

By 1983 peregrines were found nesting on bridges and buildings throughout the eastern seaboard, and in 1987 The Peregrine Fund released its 2000th peregrine. Peregrine falcons were back! In 1999 they were removed from the federal endangered species list. Since that time the population has steadily increased and in 2003, peregrines nested on the natural cliffs of the New Jersey Palisades.

People & Peregrines: A Modern Success Story

The successful recovery of peregrines is in large part due to the dedication and hard work of many outstanding biologists.

Pete McLain and Kathy Clark, Supervisory Zoologist with ENSP, were instrumental in their reintroduction and ongoing recovery efforts in New Jersey.

Today we have a stable population of peregrines, where in 2013 a total of 26 pairs occupied habitats throughout the state. Productivity was high and a total of 24 nests produced 57 young.

The core of the population nests on old hacking towers and buildings in urban areas. Four pairs continue to nest on cliff habitat at the Palisades and two pairs successfully produced 5 young total. Peregrines are currently listed as endangered in New Jersey during the breeding season, and they are closely monitored by biologists to make sure that the population remains stable.

**STAY TUNED for next week’s Part III, when we get up close and personal with the dramatic saga of the Jersey City family of peregrine falcons – the stars of their own longtime webcam reality show! **

Interesting links:


  • Cade, Tom J.; Burnham, William. 2003. Return of the Peregrine: A North American Saga of Tenacity and Teamwork.
  • Clark, K.E., Y. Zhao, and C. Kane. 2009. Organochlorine pesticides, PCBs, dioxins, and metals in postterm peregrine falcon (Falco peregrinus) eggs from the Mid-Atlantic states, 1993–1999. Arch. Environ. Contam. Toxicol. 57:174-184.

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