UC Berkeley’s peregrine falcon chicks determined to be male

Photo of young falcons
Sean Peterson/Courtesy
During Banding Day on May 12, UC Berkeley’s three new peregrine falcons were all determined to be male. The gender of peregrine falcons is based on their leg width, with male peregrine falcons being about two-thirds the size of females.

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Three fuzzy gray-white lumps of fur practice flapping their tiny wings in their nest within the Campanile. Although they are still being fed by their parents, these falcon chicks are quickly learning how to walk, run and eventually fly.

On May 12, UC Berkeley’s three new peregrine falcons were all determined to be male during Banding Day. Each chick received one band from the national Bird Banding Laboratory with a unique nine-digit number, along with a four-digit visual identification band that allows people to more easily identify the birds from a distance.

“Right now, they are mostly doing a lot of napping, but in about a week, it’s going to get really exciting as they will take time to run around the tower like crazy little toddlers,” said Sean Peterson, a campus doctoral student and social media director for Cal Falcons. “They will be trying to flap their wings and learn how to move and run. It’s just a really fun time when they kind of leave the nest and explore the top of the tower more.”

Peterson said watching the falcon chicks reflects his own experience raising a toddler at home. Resembling humans, peregrine falcons are affectionate to each other, play together and develop personalities, according to Peterson.

However, some falcon behavior is completely “foreign to the human experience,” such as eating their eggs that do not hatch, Peterson added. He noted that he enjoys teaching people about natural peregrine falcon behavior.

The gender of peregrine falcons is based on their leg width, with male peregrine falcons being about two-thirds the size of females, Peterson said. Since the legs of peregrine falcons are one of the first body parts to stop growing, observing small legs is a likely indication of males.

East Bay Regional Park District volunteer raptor coordinator Mary Malec added that there are a few ongoing research projects by the Predatory Bird Research Group at UC Santa Cruz on the peregrine falcons. They collect wing samples to determine mercury levels, which allows them to see the level of environmental toxicity in the Bay Area.

Additionally, Cal Falcons’ annual public naming contest began May 12. The first round is open to suggestions from the public across social media platforms, and the second round will be an open vote from four or five finalists Monday.

Other ways members of the public can be involved with Cal Falcons is by volunteering or contacting the organization if they see a chick on the ground.

Currently, Cal Falcons is working on putting signs up around campus in case people find the chicks on the ground. Malec said people without bird handling experience can get hurt trying to pick up falcons, as they may get bit or get talons stuck in their hand.

Cal Falcons will also conduct a presentation for kids at the Berkeley Public Library. The group will put together an online classroom tool with the Lawrence Hall of Science, buy binoculars to distribute to anyone who wants to see the falcons and potentially hold an in-person exhibit, according to Peterson.

“(From) a low of only two known nesting peregrine falcons in 1970, the numbers are improving greatly so that peregrines were on the endangered species list but have been taken off the list,” Malec said. “They are still a rare bird in the world and rare in California. They still need protection and are a protected species, but it’s kind of a remarkable recovery story to go from two known nesting pairs to a pretty full recovery.”

Contact Serene Chang at [email protected] and follow her on Twitter at @_serenechang .