Flying high
Peregrine falcon population likely growing statewide
Populations of the peregrine falcon are continuing to climb in Pittsburgh and likely throughout the state.
The formerly federally endangered falcon — the fastest bird on earth, clocked at morethan 200 mph in a stoop — was decimated by the effects of the pesticide DDT by the mid-1900s. There weren’t any recorded peregrine falcon nests in the state between about 1959 and 1987, according to the Pennsylvania Game Commission.
After a reintroduction program, the falcon’s fortunes changed with healthy populations and Pennsylvania’s delisting of the birds from the state threatened list in 2021.
This past week, three peregrine chicks in a nest atop the University of Pittsburgh’s Cathedral of Learning have been voraciously eating birds brought in by their dad, named Ecco.
Their mother, Carla, feeds, warms and watches over them at their cathedral aerie.
The National Aviary offers a free public webcam to watch the falcon family’s home life until the young leave the nest, sometime in early June.
The Pitt family this year illustrates the bird’s success and proliferation in an urban environment.
The nesting failure and death of the female bird last season are emblematic of that same success — new peregrines are showing up to disrupt established breeding pairs to take their territory and perhaps one of their mates.
“We have more active sites with more peregrines than there used to be,” said Kate St. John, of Oakland. She is the author of “Outside My Window,” a blog on local nature. She has been monitoring the region’s peregrines for 23 years.
This year, she and a team of volunteers have confirmed nesting at five sites with another seven probable nesting pairs.
Other confirmed or likely breeding spots include Downtown Pittsburgh, the U.S. Steel Clairton Coke Works, and a new location, East Liberty Presbyterian Church.
Likewise, populations are are probably on the rise statewide, said Patti Barber, endangered species biologist with the Pennsylvania Game Commission.
Counting nesting peregrines is tricky
Population growth is tricky to document, especially when wildlife officials now don’t have to count them.
When the peregrine falcon was on the threatened and endangered species lists, game commission biologists and a cadre of volunteers, including Ms. St. John, went to great lengths to document every breeding pair, with the game commission banding most of their offspring.
Such intense monitoring is required when a species is on a threatened or endangered
species list.
Unlike the large and visible nests of bald eagles, peregrine falcons often nest in a small part of a bridge or a building that viewers can’t see. Often, people monitoring peregrine nests have to first find it, wait to see if food is brought in and then wait longerto see if young emerge.
In 2021, there were 73 nesting pairs statewide, according to the game commission.
The game commission recorded a 50% drop in young peregrines leaving their nests from 2021 to 2022. Of the 52 territories occupied by peregrines in 2022, volunteers were able to document successful nesting at 40% of the sites.
But given less monitoring of peregrine nests after the bird was delisted as a threatened species in 2021, the commission expected reduced population reporting, the commission said in its peregrine falcon report released in 2023.
Additionally, documenting the presence of young peregrines leaving the nest is the “most time consuming and difficult life stage to monitor,” according to the report.
“My gut feeling is the numbers are still going up,” Ms. Barber said. The agency monitors the birds differently since the delisting and relies more now on volunteers to provide much of the nesting information.
There also are other indications of likely breeding, Ms. Barber said.
“We do see more aggression among the falcons. It’s indicative of a maturing population,” she said.
When more individuals vie for fewer resources, more competition and aggression occur, she explained.
Currently, monitored breeding areas tend to be those most accessible to volunteers, Ms. Barber and St. John said. There are other areas where the birds could be breeding but where there are no volunteers who are able to put in several months of observation.
A nest on the Tarentum Bridge, neatly tucked in a special nesting box installed by the game commission nine years ago, “is a joy to watch,” Ms. St. John said.
Dave Brooke, of Harrison, has watched and photographed those falcons raising 24 young since 2018.
Typically, he starts watching in January and February, when the birds start courting at their nest site, and he observes them until the young leave the nest around June.
It’s an interesting process, Mr. Brooke said.
“You see the young starting to walk around the bridge, and they do a lot of wing flapping, trying to figure out, ‘Do these things work,’ ” he said.
“You see the falcons learn to rip apart a carcass, which is training for them to feed themselves.”
Peregrine nest watching takes time, some luck and good optics such as a pair of binoculars, Mr. Brooke said.
“For the casual observer,” Mr. Brooke said, “these birds breed totally under the radar.”