WORTH TWP — Ospreys have made a comeback in Pennsylvania thanks to the efforts of volunteers and state agencies — including a group that worked to reintroduce them at Moraine State Park.

At their Jan. 31 meeting, the Pennsylvania Game Commissioners voted to remove osprey from the state's list of threatened species. Their agenda noted that there are at least 50 nesting pairs of the birds in the state, including at least 10 in each of the state's four watersheds.

They will still be monitored and are still protected under the federal Migratory Bird Treaty Act, which means it is a crime to kill one or destroy its nest or eggs.

Nicknamed the “fish hawk” because their diet consists mostly of fish, the birds have dark brown wings, a white breast and a wingspan of up to 6 feet.

They are listed as “least concern” on the International Union for Conservation of Nature and Natural Resources' Red List of Threatened Species, which reports that their numbers worldwide have been increasing for 40 years.

The osprey population in Pennsylvania was down to zero during the 20th century because of the use of harsh pesticides like DDT and destruction of their habitats, but during the 1980s and '90s groups around the state worked to reintroduce the birds to habitats near lakes and rivers.

Elizabeth Wilson, a board member with the Moraine Preservation Fund, said the group is aware of three nesting pairs of osprey near Lake Arthur.

One of the nests at Lake Arthur is visible across the water from the McDanels Boat Launch on the lake's north shore and the preservation fund sets up a telescope to view them during the summer.

If they know where to look, visitors to the park can watch the birds diving to catch fish from the shore or while on board the preservation fund's pontoon boat, Nautical Nature.

“It's quite fun to see them dive after fish, that's why they got the nickname fish hawks because they are good anglers,” Wilson said.

Though the change in the bird's status is encouraging, the work to keep their habitat safe is never-ending, Wilson said.

“There are so many things that are man-made that can interfere with them and cause death, we still have to be diligent. We have to make sure we make our lakes clean, free of debris and free of broken fishing lines,” she said.

The effort to reintroduce osprey to Lake Arthur was done from 1993 to 1996 by a group of volunteers from the preservation fund led by county resident Wes Hamilton.

Bringing osprey to the area was a chance to undo some of the harm that had been done to nature by humans in the past, said Ruth Roperti, a retired elementary school teacher who was involved with the effort at Moraine.

“You're keeping the natural balance of the environment,” Roperti said. “Every time you remove something, if something is not in your environment anymore, it changes the balance of plants and animals,” she said.

Each year during their efforts, young ospreys were taken from nests near the Chesapeake Bay in Patuxent River, Md., and flown by helicopter to Western Pennsylvania. They were placed on a hacking tower, a wood platform built on the lake, where volunteers would care for them until they were big enough to fly on their own.

Hacking refers to a process where chicks are relocated and nurtured until they are large enough to fly and migrate. The method for rebuilding the osprey population was developed in 1979 by Larry Rymon, a biologist and former professor at East Stroudsburg University.

The osprey would then migrate to South America where they would live for between three and five years, until they were old enough to mate and return to Pennsylvania.

The birds are not protected by laws in most South American countries, so many would not survive, but in 1996 an adult osprey returned to Lake Arthur with a mate and they raised three young, which started the lineage of today's birds.

In total the group brought 99 osprey to the park over four years. Members had planned to bring more in 1997, but decided it wasn't necessary.

Seeing an adult osprey return to the exact location it was raised after flying thousands of miles was a victory for the group.

“That was a pretty special time,” Roperti said.

Twenty years later, some of the volunteers still keep tabs on the birds and are happy to see their numbers continuing to increase.

“I am very pleased to hear that and feel that the Moraine Preservation Fund played a role in that. It's great news,” she said.

Lake Arthur is not the only habitat for osprey in the area. They used to nest at Glade Run Lake in Middlesex Township, which is currently being restored, and along the Ohio River near Rochester, Beaver County.

In coming years, members of the Preservation Fund hope to set up a camera near one of the osprey nests that would be able to provide a live video stream of the birds rebuilding their nest after returning from the south in March.

The group is applying to the Game Commission, which must grant permission, and it is looking into grants or fundraising to cover the expenses, Wilson said. For more information, visit morainepreservationfund.org.