Prairie & Peregrine Falcons Blog Posts

The 2022 prairie and peregrine falcon monitoring season at Pinnacles National Park is almost here! It will begin officially on January 18th, when the park will implement its annual raptor advisories. The monitoring season corresponds with the falcon breeding season, and the monitoring-informed advisories help rock climbers and off-trail hikers avoid disturbing these amazing park predators when they are most vulnerable.

The falcon monitoring team at Pinnacles National Park began their field season in January. They started off noting which pairs of prairie and peregrine falcons were staking out which cliff faces as nesting territories. Now, after recording all of the season’s small dramas, they’ve watched the newest generation of falcons take to the skies. It’s on the small side, but a bit bigger than last year’s.

Falcon numbers at Pinnacles have been fairly stable over the years. And while this breeding season is not over, if all current nestlings survive and manage to leave their respective nests, nest success will be a bit below average. But there are a couple of interesting dynamics at play if we look closely. One is the still-mysterious relationship between the two falcon species, both of which rely on the same cliff sites for raising young.

A pair of peregrine falcons has been active on Alcatraz Island since January 2019. While it is not unusual to see peregrines on Alcatraz during the fall and winter months, they usually depart by February. But last year, the peregrines remained active on the island through the spring and summer months. This year, on March 3, a photo was taken of the peregrines mating on the Alcatraz Water Tower. If are now nesting on Alcatraz, it will be the first time in recorded history.

Waterbirds, which nested on Alcatraz Island long before people built upon it, have been reclaiming parts of the island in recent decades. But Alcatraz Natural Resources staff hadn't seen anything quite like the 2021 nesting season. It was one for the record books, with numbers far surpassing previous years' estimates. It’s been quite a journey for one species in particular—the Brandt’s cormorant. The Island's great blue herons and peregrine falcons also had a good year.

Pinnacles' captivating, cliff-nesting prairie and peregrine falcons wrapped up their 2023 breeding season in late June. A normal number of adults nested, and visitors did their part to shield the birds from disturbance. Still, nest success was low, especially compared to the high numbers of fledglings raised in 2021 and 2022. What could explain some of that variability? Wildlife Biologist Gavin Emmons has a compelling hypothesis about one factor that may be at play.

Driving up from Louisiana to begin my internship with the San Francisco Bay Area Network, I was warned about how hot Pinnacles National Park would be. I thought California hot and Louisiana hot had to be different and remember saying “at least I’ll be able to impress them with my heat tolerance.” Spoiler: that did not happen. The falcon monitoring work done in Pinnacles is intense, even on the “fun tour.”

After a day of falcon monitoring, Wildlife Biologist Gavin Emmons led me and two other interns on a hike to visit the High Peaks at Pinnacles National Park. We had a side mission of removing a climbing advisory sign. Climbing, as in rock climbing, is a popular sport that involves scaling rock walls, indoors and/or outside. Pinnacles is a popular spot for those who enjoy outdoor rock climbing. But Pinnacles’ rock formations are also popular with the park’s nesting falcons.

The raptor monitoring season is finishing up at Pinnacles National Park. When it began, it seemed unlikely that the park’s breeding falcon pairs could be even more successful than they were last year when they raised an impressive 40 young. Yet here we are. This season, nine prairie falcon and four peregrine falcon pairs nested and all pairs fledged a total of 46 falcon young! That's a tie with 2013 for the highest falcon fledgling total since monitoring began.

Prairie and peregrine falcons have returned to nesting territories in Pinnacles National Park for the 2022 breeding season! So far, falcon monitoring staff and volunteers have confirmed prairie and peregrine falcon pairs occupying nine and four territories respectively. As of late April, all have laid eggs and/or are now raising nestlings! The monitoring team has also confirmed that five other raptor species are nesting in the park, including two long-eared owl pairs.