ACADIA NATIONAL PARK — Peregrine falcons have returned to Acadia National Park again this year, prompting closure of three popular hiking trails in the park for several months.

Nesting peregrine pairs apparently have settled in for egg laying and chick raising on Champlain, Penobscot and Beech mountains and are actively defending their nesting territories, park biologists reported this week. To protect the birds from disturbance or harassment, the Precipice Cliff Trail on Champlain, Jordan Cliff Trail on Penobscot, and Beech Cliff Loop Trail will be closed to hikers until mid- or late August.

Park officials will post signs and maps at trail heads, parking areas and visitor centers about the closures. The Beech Mountain trails that will remain open are Beech Cliff Ladder Trail, Canada Cliff Trail, Valley Trail and the Canada Cliff Climbing routes.

Deputy Park Superintendent Len Bobinchock said Tuesday the nesting pairs could lay eggs as early as next week. The trails must remain closed until the young birds are independent of their parents and nesting territories.

The falcons, nearly driven to extinction because of pesticides and habitat loss, have made a strong comeback in the eastern United States, including the three Acadia locations. The park was selected as a reintroduction spot for the birds in 1984, when young captive-bred peregrines were released from the cliff above Jordan Pond.

By 1991, the first pair of peregrines had successfully nested on Champlain Mountain, and have returned annually to raise young. In 1995, a second pair established a nest on Beech Cliffs, returning the following year to raise one chick. A third pair attempted to nest at Jordan Cliffs last year, but was unsuccessful. Twenty-one chicks have been raised in Acadia over the last six years.

The birds are particularly sensitive to human disturbance that comes from immediately above their nesting area or directed at the nest site. Harassment can lead to nest failure and loss of chicks.

This weekend, on April 19 and 20, a major portion of the paved Park Loop Road will be restricted to bicyclists and pedestrians. If the weather permits, all of the park’s roads will be open to motor traffic beginning April 20. Bobinchock said he expects the carriage roads will be closed this weekend, and possibly into next week, due to the mushy surface of the roads.