Peregrine Falcons May Be Nesting on Alcatraz

On March 3, the Island peregrine pair was spotted mating on the Alcatraz Water Tower.

NPS / Tori Seher

March 2020 - A pair of peregrine falcons has been active on Alcatraz Island since January 2019. One has leg bands identifying her as Lawrencium, a female hatched on the UC Berkeley Campanile in 2018 (a UC Berkeley public poll named the bird after an element discovered at the University). 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, much to the dismay of all the nesting waterbirds. It seemed no bird was safe from the peregrines as they regularly knocked other birds from the air, sometimes right in front of unsuspecting tourists. Their prey included the usual pigeons and starlings, but also a Canada goose, western gulls, pigeon guillemots, great blue herons, and American crows. So far, the Island’s resident pair of common ravens have escaped death – but they and the peregrines can be observed in aerial combat almost every afternoon.

Since they were seen mating, the male peregrine has also been seen sharing prey with the female before she disappears to somewhere along the cliff below, where biologist Tori Seher suspects they have a nest.

NPS

This year, on March 3, a photo was taken of the peregrines mating on the Alcatraz Water Tower. Several days later, the male falcon repeatedly dive-bombed the Island biologist near the western cliffs of the Island, indicating the likely presence of a nearby eyrie (bird-of-prey nest). Since then, the male has been observed sharing prey items with the female, before she disappears again somewhere along the cliff. If the peregrines do have a nest site on Alcatraz, it will be the first time in recorded history.

For more information

• Contact Alcatraz Biologist Lidia D'amico

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