Peregrine Falcons, by Wes Laraway


Wes LarawayNY Wildlife Rescue Center

         When I was asked if I could write a short article about Falco Peregrinis I gladly agreed.  I never get tired of researching, or sharing what I have learned about wildlife with others.    Our rescue facility, located here in Middleburgh, has helped several Peregrine Falcons in the past.  We currently have one male Peregrine Falcon in our care.  Falco Peregrinis means “Wandering Falcon.”  Old-timers (and the early bird books) refer to Peregrines as the “Duck Hawk.”  The Peregrine is a very common medium sized falcon that is found worldwide on every continent except for Antarctica.  Worldwide, their numbers are doing well, with some estimates of over 140,000 Peregrine Falcons, but that number would be very difficult to confirm.

Peregrine Falcons have been prized by falconers for over 3,000 years, and Peregrine Falcons also get the honor of being the “fastest animal on earth.”  Normal flying speed is between 25 to 35 MPH but they have been clocked doing over 220 MPH when they go into a fast dive (or stoop) while hunting.  Many airports employ falconers to use Peregrines to keep other birds away from the airport to avoid collisions with planes.  Peregrines were used during World War II to try to intercept homing pigeons with messages. The oldest Peregrine Falcon in the wild was banded in Minnesota in 1992 and was seen again in 2012, but 20 years of life is rare in wild falcons.  Over half of the chicks born to wild falcons will die (from a variety of causes) in their first year of life.  We are very fortunate to have a nesting pair of wild Peregrine Falcons on Vroman’s Nose.   I have helped two of their chicks in the past.

Starting in the 1940’s, due in part, to the use of pesticides like DDT we noticed a steady decline of most bird of prey species until biologists figured out that the pesticide was being ingested through their prey.  This caused the shells of their eggs to weaken to the point that the shells would break during incubation.  By 1964 there were no wild Peregrines east of the Mississippi River.  By 1974 there were fewer than 325 nesting pairs in America.    Since banning DDT in the 1970’s, birds of prey have made a slow recovery.  Birds of prey continue to be protected under the Federal Migratory Bird Act.  In 1999, Peregrine Falcons were removed from the Federal Endangered Species List but they still remain on the New York State Endangered Species list and are still on the Threatened Species lists in many other states.  Up until around 20 years ago, most Peregrine Falcons found in the wild were captive-bred and released in an attempt to get nesting pairs started around the nation.  By 2004, reintroduction was working well with reintroduced captive-bred falcons.  We had 50 nesting pairs in New York; today that number is around 100.  New York City currently has one of the highest Peregrine Falcon populations in the world.  Cities, and the New York State Department of Transportation, welcome Peregrine Falcons because studies show that around 80 percent of their diet is pigeon.  Pigeon feces are acidic and can be a huge problem with corrosion on bridges and buildings. The falcons help keep the pigeon population at acceptable levels and prevent millions of dollars in damage from large numbers of pigeons roosting and nesting on the structures.

Initial attempts to reintroduce captive raised Peregrine Falcon chicks by soft release (hacking) often were failures.  Great Horned Owls and other predators often killed the birds at night while they were sleeping. Chicks that were released near urban areas often had better odds due to fewer natural predators, more prey (pigeons) and more people watching them on webcams to report potential problems.

Female Peregrines are bigger than the males.  Females weigh between 1.5 and 3.5 pounds.  Males weigh between  1 pound and 2.5 pounds. Peregrines’ diet consists of between 1500 to 2000 species of birds worldwide, but in North America they feed on about 300 species.   They do eat mammals, bats, and snakes, but birds seem to be the preferred prey.  It was thought that Peregrines mated for life, but in high concentrations of falcons in urban settings the males will sometimes fight for territory and a female.   Nesting sites are normally high—at least 50 feet, and over 200 feet seems to be preferred. Nests are often on tall buildings, bridges, or cliffs that are difficult to reach without flight. This provides seclusion and protection from other predators. Like Eagles, Peregrines seem to like to nest near water.  The pair return to the same nesting site every year ,where they start courtship flying and rituals between February and March. Peregrines’ winter migration takes them to warmer places with prey but recent studies show that some birds do not appear to migrate if food and shelter are sufficient. A wounded Peregrine Falcon that I rescued two years ago in Middleburgh hit a house (in January) while chasing birds at a bird feeder in Indian Acres.

Once a nesting site is selected, little if any nesting material is brought to the site.  The pair will clean a small area of substrate or debris, and usually lay 3 to 4 eggs.  The female does most of the incubation, but the male will often sit on the eggs while the female takes one or two breaks during the day to feed. The eggs hatch at between 29 to 35 days, depending on conditions.  The parents will guard the nest territory for up to a mile to protect the chicks.  There have been confirmed kills on birds as large as eagles that violate the nest territory.  The parents will hunt an area 12 to 15 miles around the nest and both parents hunt to feed the chicks. After 37 to 46 days, chicks normally end up fledging (leaving) the nest, although the fledglings are still learning and dependent on the parents for food for up to 2 months afterward.  Eventually, the chicks will establish their own breeding territory between the age of one to three years of age. At that point we hope that the whole process repeats itself.

I do not remember ever seeing birds of prey when I was a kid. I do hope that will change for my grand children and our future generations.  When hiking Vroman’s Nose, please be respectful of the nesting Peregrine Falcons. Hopefully, you will see them while on the summit.

This article was first published in the 35th Anniversary booklet for the Timothy Murphy Run, held on October 6th, 2018, and is reprinted here with permission. Photo credit to Deb Bechtold.