In August 1992, state biologist Charlie Todd ascended Borestone Mountain to tend to five captive peregrine falcon chicks. He was met with an unforeseen obstacle: the birds themselves. “I crawled into the hack box to collect fecal swabs and administer antivirals on the falcons,” Todd said. “But I forgot my ear plugs, and the birds were screaming.”

A hack box is an artificial eyrie made of wood and used to rear young peregrines. It was designed centuries ago by falconers to house peregrines prior to training flights. The boxes, which resemble small jail cells with vertical bars, are placed on ledges and cliffs where wild peregrines often breed. Ranging in age from 3 to 4 weeks old, the young are fed dead Coturnix quail by attendants via a long PVC pipe entering the top of the hack box. From the chicks’ perspective, food magically appears inside the box, akin to DoorDash deliveries minus the doorbell. Peregrines are kept from seeing their caretakers to prevent imprinting on humans. Daily food deliveries continue for almost two months, well after the raptors fledge.

Raising peregrine chicks in artificial eyries was necessary because of widespread use of DDT — a highly toxic, persistent pesticide — from the 1940s to 1972, when DDT was banned in the U.S. by the Environmental Protection Agency. The raptor’s ingestion of this chemical via its prey had rendered its eggshells too thin to survive the weight of an incubating female. Robbed of the ability to raise young, the falcon population entered a death spiral in Maine and elsewhere. By the mid-1960s, breeding peregrines had vanished from the skies and cliffs east of the Mississippi River.

The late Dr. Tom Cade, former director of The Peregrine Fund, once told me, “Reintroducing a species that’s been extirpated is among the most daunting tasks biologists will ever face.” Beginning in the early 1970s, Cade and his cohorts perfected the art of inducing captive adult peregrines — on loan from falconers across North America — to reproduce in the “Hawk Barn” at Cornell University. Cade was the architect of the fund’s highly successful peregrine hacking program. Since 1974, in collaboration with various states and Canadian provinces, the fund has reintroduced over 6,000 peregrine falcons into the wild across 37 states and every province.

Maine conducted its first peregrine release in 1984 in Acadia National Park. “Ironically,” said Todd, “we then had to shift hack locations because a new territorial pair arrived in Acadia National Park in 1988. So we moved our hacking operations to Borestone.”

In 1988, as the state’s regional wildlife biologist in Greenville, I visited the Borestone hack site several times with Todd and his peregrine release crew. Back then, Borestone was a 1,639-acre sanctuary owned by National Audubon. In 2000, it was transferred to Maine Audubon. For many years, Jack and Ruth Anne Dunstan, the sanctuary’s year-round caretakers, lived in a cabin atop the mountain from spring until snowfall. The couple wintered in nearby Monson.

The Dunstans acted as surrogate grandparents to the falcons’ human caretakers, many of whom were college students majoring in natural science. Shortly before the birds fledged, at 35 to 40 days of age, the bars on the west side of the box, facing Sunrise, Midday and Sunset Ponds, were opened. From a blind, I watched young peregrines venture outside for the first time. While firmly gripping a horizontal pole with their talons, they flapped their wings awkwardly, tipping forward, then over-correcting by leaning backward. It was comical, like watching a toddler learn to walk. On day two, a dragonfly buzzed two peregrines perched on the pole. One bird instinctively reached to grab the dragonfly with a foot, missed, fell over backward, and was airborne. Its maiden flight was unsteady, ending in a crash landing atop the hack box. By the third day, the bird had learned basic flight skills and returned to the pole clutching a dragonfly.

The recovery of peregrine falcons was highlighted nationally in 2023 during the 50th anniversary ceremonies of the Endangered Species Act of 1973. In hindsight, it seems criminal that we allowed our collective use of toxic pesticides to drive this remarkable species — and others — so perilously close to extinction. Thanks to Cade’s foresight and dedication, over 3,000 breeding pairs of peregrines now nest in North America. Although the species was removed from the federal Endangered Species List in August 1999, it remains on Maine’s Endangered Species List because their numbers here remain relatively low. In 2024, according to Dr. Erynn Call, Maine state raptor specialist, 33 pairs of peregrines nested in Maine, fledging 46 youngsters.

“Borestone became a favored, reliable hack site,” said Todd. The mountain served as great release site, in part because peregrines did not return to it as breeding adult birds. Had they done so, they likely would have killed the hack-site fledglings.

“More than 23 percent of 154 peregrines hacked at seven different locations first tested their wings there,” said Todd. In 1993, he stopped releasing young peregrines at Borestone due to the arrival of an adult peregrine at nearby Barren Mountain.

Todd’s encyclopedic knowledge of Maine’s peregrines is impressive. “In the 1990s,” he said, “a Borestone-raised peregrine decided she preferred Boston’s city life to the wilds of Maine.” Successfully establishing a territory in the city required her to kill an adult female peregrine falcon that nested for many years on a ledge of the Customs Building. The Boston Globe ran a feature story of the Sopranos-style hit in a piece titled “A Coup at the Coop.”

In 1989, Todd retrieved a dead banded peregrine near the Piscataquis River in Dover-Foxcroft. “I presumed it was from the nearby Borestone Mountain hack station,” Todd said. “But that assumption was way off. It was a juvenile peregrine wearing a Danish bird band, which it had received in western Greenland seven weeks earlier. The distance these birds travel is amazing.” Their Latin name, Falco peregrinus, means “wandering falcon.” And wander they do — juvenile peregrines banded in Alaska have been recaptured several months later in Tierra del Fuego at the southern tip of South America.

The success of the species’ recovery in Maine is a direct result of Todd’s leadership and dedication, but he’s quick to share the praise. “We wouldn’t have been able to re-establish peregrines in Maine,” Todd said, “without the support of Audubon, The Peregrine Fund, U.S. Fish and Wildlife Service, National Park Service, U.S. Forest Service, Maine Bureau of Parks and countless others. And Borestone Mountain itself: Of all the former Maine hack sites, none were used as many years or achieved greater success than the one at Borestone Mountain Sanctuary.”

Ron Joseph is author of Bald Eagles, Bear Cubs, and Hermit Bill: Memories of a Maine Wildlife Biologist, published by Islandport Press