ZION NATIONAL PARK — The park will close climbing routes that are used by nesting peregrine falcons beginning this weekend.

The routes will temporarily close March 1 to protect the nesting success of this bird, which is in recovery from endangered species status. The closure date is based on analysis of information collected from 2001-2013 regarding the peregrines' arrival time to their nesting cliffs in the park.

The cliffs that will close are Angels Landing, Cable Mountain, The Great White Throne (beyond single- and double-pitched climbs), Isaac (in Court of the Patriarchs), the Sentinel, Mountain of the Sun, North Twin Brother, Tunnel Wall, the East Temple, Mount Spry, the Streaked Wall, Mount Kinesava, and the Middle Fork of Taylor Creek. All other cliffs will remain open to climbing.

Wildlife biologists will monitor the nesting activity of the falcons throughout the 2014 breeding season. Cliffs that have been closed but are not being used for nest sites this year will be reopened when nest locations have been determined, typically by late April or early May. Those cliffs being used this year will be monitored until the chicks fledge, usually in late July, and then will be reopened to climbing.

The falcons were listed as an endangered species in 1970 under the Endangered Species Act. Their decline was primarily due to the effects of the insecticide DDT. The U.S. ban on DDT in 1972, as well as the success of captive breeding programs, have helped the falcons recover across North America, and the species was delisted in 1999.