Usually, Kate St. John's home page - a Web cam of a pair of nesting peregrine falcons - is pretty tame. Sunday, it was birds gone wild.
When St. John tuned in early that morning, she was met with a rare sight: two birds locked in a death battle, talon to talon, tumbling perilously on a high ledge of the University of Pittsburgh's Cathedral of Learning.
There was no audio, but St. John could tell there was screaming. One of the birds wrestled the other to its back, stabbing at its chest with its beak, drawing blood.
It took her a minute to realize what was going on. A third falcon - a male - was trying to take over.
St. John flew into action, saving two dozen Web images, which are not archived, during the 20-minute battle.
Now, ornithologists are hailing the photos as a phenomenal documentation of an event rarely seen outside ornithological circles, much less recorded.
"We got lucky to catch a fight in progress," said Tony Bledsoe, an ornithologist at the University of Pittsburgh's department of biological sciences.
Any "active" behavioral shots are highly sought-after in the bird world, said Greg Butcher, director of bird conservation for the National Audubon Society.
Mating shots are common, sure. And definitely birds singing.
"But to have it continuously throughout the fight, that might be unique," he said.
Even though the photos are a bit dark, even though they're a bit blurry, "boy, are they stunning in aggregate," Bledsoe said.
This bird's-eye view, so to speak, of falcon-fighting and spouse-stealing offers new insight into bird behavior, he said.
"We have a detailed set of images of how the fight progressed and how the female was reacting," Bledsoe said.
Ornithologists know that males - and even females - sometimes take over another bird's nest. Sunday's photo sequence gives them more clues to how it happens.
One of the things Bledsoe found most interesting was the reaction of Dorothy, the female. She came close and watched, intensely interested. At one point, she even circled the two males to get a different vantage.
As one gained control, pushing the other to the ground and pecking his chest from above, she moved within inches.
No one knows for sure, Bledsoe said. But contained in that fight is pertinent information for her. If the intruder were to win and kill Erie, her mate, Dorothy would need to decide whether to accept the victor.
"She is going to be dependent on that male to provision her offspring," Audubon's Butcher said. His prowess in the fight might show her how he would capture prey or defend the nest against other interlopers.
As the two birds tumbled and stabbed, much was at stake for Erie, too.
"He's already raised 18 young with Dorothy since 2002," Bledsoe said. "That means he's a pretty old bird. At this point in his life, the probability of him losing a territory and finding another one is low. He has a territory that's ideal now. He is likely to fight to the death to retain it."
As a mesmerized St. John watched - frantically right-clicking to save the images - the two birds rolled toward the brink of the 40th-floor ledge.
And then they went over it.
They landed briefly in a gully, but St. John couldn't see what happened next. The Web cam refreshes every 15 seconds, and by the next shot the two males were gone.
Dorothy alone stood on the ledge, looking into the sky.
St. John hastily dialed Bledsoe, who went over to have a look. No males. All silent.
Were they fighting somewhere else?
Was one or the other dead?
Erie had fought off other challengers in years past. Could he do it again?
Bledsoe and others searched around the base of the building. No dead birds.
But later that day, a lone falcon returned. It settled on Erie's perch. It went to one of Erie's caches of food and ate. It didn't engage in any sort of courtship behavior with Dorothy.
It looked as if Erie had won. He's a tough old bird who has fought off other intruders before - and appears to have passed on some of his survival tactics to his progeny.
In 2003, his son Louie wrested a nearby falcon nest from its 12-year-old patriarch, Boris. Louie bit his head off.
"It's tough out there," Bledsoe said.
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Contact staff writer Sandy Bauers at 215-854-5147 or firstname.lastname@example.org.