ACADIA NATIONAL PARK (AP) – Seven peregrine falcons have successfully hatched at two nesting sites, but eggs at a nest at Jordan Cliff failed to hatch for the third year in a row.

Park officials are unsure of why the Jordan Cliff site has failed to produce. They also are unaware of the fate of a fourth nest site, at Valley Cove on the western side of Somes Sound, because of the secretive nature of those falcons.

But officials are pleased about the other nest sites, where seven chicks have hatched. Four of the chicks are nesting on the Precipice on Champlain Mountain, and three are on Beech Cliff.

Peregrine falcons are listed as an endangered species under the state Endangered Species Act.

“Four chicks is very good,” said Ranger Angi King Johnston. “On a natural cliff face, such as those at Acadia National Park, four is about as many as you’ll ever see.”

At Valley Cove, it’s hard to determine if any birds have hatched because the breeding pair there is very secretive, King Johnston said.

“Where the Precipice pair is very obvious and very vocal, the female in particular, and easy to be seen, the Valley Cove pair is the exact opposite,” she said.

Park officials are trying to figure out why the nest at Jordan Cliff has failed to produce.

After it was determined two weeks ago that the site had failed again, a park employee clambered down the cliff using rock climbing gear and found a cracked, fly-ridden egg in the nest.

One possible explanation is that the nest site was attacked by a great horned owl, the falcon’s primary nighttime predator.

“We’re not exactly sure what’s going on there,” King Johnston said. “We’re hoping that the analysis of the egg will give us a clue.”

Because of the nest failure, the Jordan Cliff Trail and cliff has reopened to the public. Trails near the nests have been closed because nesting falcons are vulnerable to human disturbance such as hiking or climbing, park officials said.

Cliffs at the Precipice, Beech Cliff and Valley Cove will remain closed to protect the falcons nesting at these sites. Rangers anticipate the Precipice and East Face trails to open in late July and Beech Cliff likely to open in early August.