The soaring cliffs of Yosemite National Park are beloved by rock climbers, with thousands visiting California’s Sierra Nevada mountains yearly. Yosemite is also home to 17 pairs of peregrine falcons, and these majestic birds of prey owe some of their breeding success to the climbers with whom they share the park’s most iconic rock formations.
For several decades, peregrine falcons were completely absent from Yosemite. After the last pair were seen in 1941, they appeared to have vanished from the park, with their numbers dwindling due to the use of pesticides and insecticides like DDT. Although DDT was outlawed in 1972, peregrine falcons had already suffered immensely, with DDT causing the birds to lay eggs with extremely fragile shells prone to breakage. They were named a federally protected endangered species in 1970 when only a few hundred pairs remained nationwide.
So it was a massive surprise in 1978 when a quartet of climbers discovered an active peregrine falcon nest while climbing the southeast face of Yosemite’s famous 3,000-foot-high El Capitan granite rock wall. Following the discovery, the rock-climbing community was instrumental in helping the Santa Cruz Predatory Bird Research Group launch a bold rescue plan. Climbers were tasked with removing the thin-shelled eggs, placing them in protective foam containers, and carrying them back down to the ground. The climbers were forced to keep their wits about them as the peregrine falcon parents repeatedly flew close to them, sometimes even making contact with their packs.
The eggs were carefully monitored and incubated in a laboratory. After the chicks had hatched and were deemed ready, the climbers carried the baby birds back to their nests in small fabric cages. In most cases, the parents began feeding and caring for the baby birds within half an hour. Over 1,000 peregrine falcon chicks were released in this way, helping to ensure their survival in their natural ecosystem.
More recently, climbers have been doing their part to assist the park’s peregrine falcons in a less hands-on way. Peregrine falcons often choose sheer, high-altitude nesting sites because of the natural protection from ground-based predators. However, these sites are sometimes traversed by the expert rock climbers who flock to Yosemite. The Peregrine Falcon Protection Program closely monitors the park’s peregrine falcon population and closes specific climbing routes that are home to vulnerable nest sites. The routine monitoring effort, which takes place every year between March and mid-July (when the fledglings leave their nests), ensures that the young birds are protected while also ensuring that climbers retain access to the vast majority of the park’s climbing routes. A maximum of 5% of routes are ever closed at one time.
Climbers and fliers:
- In 2009, when the protection program began, the park hosted just eight breeding pairs. This year’s 17 pairs produced 25 chicks.
- Peregrine falcons are the world’s fastest animals. They can exceed speeds of 200 miles per hour when diving.
- The International Union for Conservation of Nature lists rock climbing as a threat to the survival of peregrine falcons, as the presence of humans can scare away parents from their nests, leaving them exposed and unprotected.
