The Canadian Peregrine Foundation

Pitt's Peregrine Falcons Defend Cathedral of Learning Nest From Intruder in Bloody Clash of Talons and Beaks
Tuesday, 20 March 2007
University of Pittsburgh: NewsFromPitt

Web camera captures rare footage of mating season row and may provide clues on falcon behavior

PITTSBURGH-A quiet Sunday morning for the peregrine falcons living atop the University of Pittsburgh's Cathedral of Learning erupted into a bloody struggle for territory when a third falcon attempted to overtake their nest.

Neither of the Pitt falcons appears to have been injured during the 20-minute melee, but a Web camera that monitors the falcons' nest recorded the battle, making for rare and informative footage, said Anthony Bledsoe, a lecturer of biological sciences in Pitt's School of Arts and Sciences who helps monitor the birds.

“Fights over nests and territory are pretty common, but nobody ever sees the fight,” Bledsoe said. The footage could help people who study peregrine falcons better understand how a new male-or sometimes female-takes over a nest, Bledsoe said. Researchers often find a new parent in a monitored nest, but lack solid evidence suggesting how the interloper took charge, he said.

Images of the fight show a third falcon invading the nest of Erie and Dorothy, who have nested on the Cathedral's 40th floor since 2002. Erie, the male, was wrestling with the intruder when Kate St. John, a volunteer for the Western Pennsylvania Conservancy (WPC) who monitors the Pitt falcons, happened to check the Web camera around 9 a.m. Sunday, March 18; she took still images with the Web camera as the row raged.

St. John's photos show Dorothy looking on as Erie and the interloper lock talons and lash at one another's chests with their beaks. Erie eventually flipped the other bird over, stabbing his chest before the two rolled out of the nest in a flurry of feathers. The last shot is of Dorothy gazing skyward while, as St. John figures, Erie chases the intruder away. St. John could not tell from the images if the triumphant falcon was Erie, but assumed from the normal way in which the victor and Dorothy behaved-without the bowing and circling rituals of new courtship-that Erie had won.

“It was scary because if it got really bad one of them was going to die,” St. John said. “They fight to the death. Erie has ruled the nest since 2002 and raised 18 fledglings. He can't afford to lose the site. How could he start over at his age? If a newcomer fights him, he would have to be killed. He has everything to lose. The fact that they fell off the nest probably saved a life.”

Peregrine falcons often fight during their March nesting season: The females are fertile and young birds without nests cruise for older falcons to overthrow. At stake are a mate, a ready-made nest, a perch (what better than the Cathedral), and feeding grounds, Bledsoe said. Falcons viciously defend or usurp a nest. A few years after Dorothy and Erie nested on the Cathedral, Bledsoe was summoned when they engaged two other birds in two hours of bloody, screeching combat outside Pitt's accounting office. The brawl broke up by the time Bledsoe arrived.

“This isn't the first time Erie has fought off an intruder,” Bledsoe said. “Another falcon tries to intrude every year.”

Erie and Dorothy also spawned a scrapper. One of their offspring, which St. John named Louie, conquered the nest at downtown Pittsburgh's Gulf Tower in 2003 when he killed and decapitated the approximately 12-year-old patriarch Boris (an elder in peregrine falcon years). Louie still rules that nest.

Despite Erie's supposed victory Sunday, a young, strong falcon like Louie will some day control the Cathedral nest, Bledsoe said.

“The day will come when another male occupies the site, either after Erie's natural death or he dies by accident or in a fight,” he said. “It's tough out there.”

To see a slideshow of Sunday's fight, visit the WPC Web site at

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