Peregrine pair fledge record number of chicks

GRAND TETON NATIONAL PARK — The public closure at Baxter’s Pinnacle and Descent Gully near the mouth of Cascade Canyon was lifted on Saturday, August 16. This area closure went into effect May 6 to protect an active peregrine falcon nest.

Due in part to the protection provided by this wildlife closure, the adult falcons successfully reared and fledged four chicks. While peregrines can lay up to five eggs, this marks the most young ever fledged at a single nest site in Grand Teton National Park (GTNP), according to park records.

After reintroduction of peregrine falcons was initiated in GTNP and the Greater Yellowstone Ecosystem (GYE) in 1980, the first successful falcon breeding in the park was documented in 1988. Over the years, the number of successful nesting pairs has risen from one in the late 1980s to as many as four pairs in recent years.

This year, a fifth nest site was discovered near a cliff area on the north side of Blacktail Butte. For unknown reasons, this new nesting site did not produce any young. In addition to the Baxter’s Pinnacle nest, one other Teton site fledged three peregrine chicks this year and a third nest fledged one chick, making a total of eight peregrine young fledged at Grand Teton in 2014.

The Baxter’s Pinnacle peregrines experienced little to no human interruption during their incubation and chick-rearing phases thanks to active support from the park’s two authorized concessioners for guided climbing services, and to the cooperation of Jackson Hole’s climbing community that demonstrated responsible behavior and respected the closure.

Peregrines are cliff nesters and can be sensitive to human disturbance, especially during their nesting period. Falcons are quite territorial and will often abandon nests to defend their territory, which leads to nest failure and low reproductive success.

Decimated by the harmful effects of the pesticide DDT, it is believed that peregrine falcons were virtually eliminated from the (GYE) by the 1960s.

In 1980, efforts to reintroduce peregrine falcons to GTNP were initiated in conjunction with similar efforts elsewhere in the GYE and western United States. Between 1980 and 1986, 52 fledgling falcons were released at several sites in the Teton Range.

After sufficient recovery was achieved, peregrines were delisted from the endangered species list in 1999. However, peregrine falcons remain a species of interest in GTNP. The Baxter’s nest area was first discovered in 2010.

This peregrine falcon pair successfully produced one chick in 2010, 2011 and 2013, before fledging four young this year.

The public closure served a second purpose: to also protect climbers from the peregrines as they will defend their nest site by dive-bombing perceived intruders. The peregrine falcon is among the world’s fastest birds, flying at 40-55 mph and diving at more than 200 mph while defending a territory or striking prey. This posed a safety risk to climbers who may have been knocked off their rock ‘perch’ and injured.

Seasonal and temporary closures for wildlife protection are common in Grand Teton to protect both wildlife and park users. Entering a posted wildlife closure is a violation that can result in a citation and fine under the code of federal regulations.