Update 7/14/2021: Two chicks fledged at each of three nests at Acadia National Park in 2021, or six in total, Patrick Kark, ornithology ranger at Acadia, told us in an email. “It has been a good season,” Kark wrote to us. “Glad all three sites made it through some extreme weather events. Two major rainstorms and an extreme heat wave. It is also nice to see fledglings back at the Precipice since they had failed in 2020.”
Thirty years after the first peregrine falcon chicks hatched during Acadia National Park reintroduction efforts, the raptor continues an amazing recovery, with month-old chicks spotted in several nests this year, and new park statistics underscoring their comeback.
Patrick Kark, ornithology ranger at Acadia, recently released a chart on the total number of peregrine falcon chicks fledged at Acadia since 1991 in four cliff-top sites including 78 at the Precipice; 31 at Jordan Cliffs; 27 at Valley Cove; and 24 at Beech Cliff.
“Through having all these nesting sites in park, as of 2020, 160 peregrine falcon fledglings have flown from Acadia, which is a huge number, huge success story,” Kark said during a webinar held last month by the Western Maine chapter of Maine Audubon.
Peregrine falcon chicks are set to fledge at three nests this year, Kark wrote in an email last week. There are no confirmed numbers yet, but peregrine falcon chicks are known to be on the Precipice, at Jordan Cliffs above Jordan Pond and at the Valley Cove Cliffs above Somes Sound, Kark wrote. Chicks appear to be around 30 days old, he wrote.
Peregrine falcon chicks survive severe rainstorm that damaged roads
It appears that a powerful June 9 rainstorm, which caused the closure of 10 miles of carriage roads, created no issues at the nest sites, Kark wrote.
While peregrine falcons continue to do well in Acadia and are thriving in most places they can be found in Maine , Kark said one big issue is that the park’s most productive nest, located on the Precipice on the east side of Champlain Mountain, has failed four times since 2011 including in 2020 during the pandemic.
Before 2011, the nest on the Precipice failed only once – in 2007 – in the 20 years prior.
Nests at the Precipice also failed in 2011, 2012 and 2018, according to data presented by Kark.
When asked during the May 12 online event how climate change could be affecting raptors, Kark said freak storms later into the spring could be responsible for unsuccesful nests. If the eggs hatched and then were hit with a couple days of heavy rains followed by near freezing temperatures, that could cause nest failure. He cited an April storm that might have caused the 2020 failure at the Precipice.
Kark said no one knows for sure what caused the nests to fail. A nocturnal predator, the great horned owl, could also be responsible, he added.
Peregrine falcon chicks an Acadia environmental success story
Despite the setback at the Precipice, five peregrine falcon chicks fledged in 2020 at the park including two at Jordan Cliffs and three at Valley Cove, Kark said during the webinar. That was down from nine fledglings in 2019.
Throughout Maine, 37 pairs, including 29 breeding pairs, were documented in 2020. Most were on cliffs and others were on buildings such as lighthouses, quarries, bridges and used osprey nests, according to the 2020 Peregrine Falcon Program Report by the state of Maine Department of Inland Fisheries and Wildlife.
Peregrines became extinct east of the Mississippi River because of the effects of the DDT insecticide and populations of other raptors such as eagles and osprey were also severely damaged. Heavily sprayed in the 1950s, DDT degraded into a chemical that accumulated in the food chain and hampered the ability of the birds to produce calcium, which is vital for producing healthy eggs, Kark said.
As a result, falcons laid eggs with shells so fragile they often shattered during nesting or failed to hatch. Because too few young were raised to replace adults that died, peregrine populations declined precipitously, according to the US Fish & Wildlife Service.
Recovery began when falcons were listed as federally endangered in 1970 and DDT was banned in 1972. Biologists began breeding the birds in captivity and preparing them for release.
Release of chicks in ’80s led to first successful nest in Acadia since ’56
According to Acadia National Park, 22 peregrine chicks were successfully hacked, or released, on Jordan Cliffs from 1984 through 1986. An adult bird returned in 1987, prompting the park to end the hacking program because the adult could prey on any released chicks.
In 1991, the first pair of peregrine falcons nested successfully on the east face of Champlain Mountain, according to the NPS. A second pair of falcons established a nest site on Beech Cliffs above Echo Lake in 1995, and a third pair of falcons established a nesting territory at Jordan Cliffs in 1996, according to the NPS.
“National Parks play an important role in preserving biodiversity, in addition to being a great place to experience nature,” retired Acadia ranger Judy Hazen Connery wrote on the Acadia National Parking Hiking Facebook group. “It’s so great to see peregrines return to our skies!!”
The park has also gained new insights about the behaviors of peregrine falcons.
Because falcons are so territorial, for example, there has only been one year – 2004 – when the park had a successful peregrine falcon nesting site at both Valley Cove along Somes Sound and Beech, or Echo, Cliffs, Kark said.
“The best guess is they are just too close to host two pairs of peregrine falcons most of the time. As the peregrine flies, they are roughly only about a mile apart and therefore too much competition and they probably keep driving themselves out.”
The bird has done so well, it was removed from the federal list of endangered and threatened species in 1999. The reintroduced breeding populations – a genetic blend of many birds involved in the captive breeding effort – remain on the state endangered list for Maine.
At the Acadia Birding Festival in early June, Angi King Johnston, a naturalist and former raptor ranger at Acadia, helped a group of birders watch a falcon perched near its nest on the Precipice. Looking through a scope from the parking lot below the Precipice, people could see the bluish-gray bird upright and sometimes preening near the nest, which is only a scrape on the cliff. “They lay eggs right on the cliff,” she told participants at the festival.
At the same Precipice parking lot, Acadia rangers this year are holding peregrine falcon watch allowing people to stop by and watch the raptors through viewing scopes and learn about their behaviors. The program will be held 9 am to noon every week day until July 23.
The program is a great way to talk to visitors about peregrine falcon conservation and about the hard work by many nonprofits and government agenices to bring the birds back to their historic ranges, Kark said.
In order to protect the nesting birds, the park in March temporarily closed hiking trails including the Precipice Trail, the Jordan Cliffs Trail, part of the Orange & Black Path and a section of the Valley Cove Trail. The trails usually open again in early August after the chicks fledge.