So, after four years of all the young hawks surviving - a "fairy tale," Schubert said - the perils of urban life may be catching up to them.
"Animals and the world of humans collide, and it's usual brutal, violent, and short - for the animals," Schubert said.
Even in the wild, two out of three young hawks never make it to adulthood, perhaps sometimes because they are unable to find food.
"They might not be the strongest, smartest, quickest ones," Schubert said, "and they don't survive." Add the compounding factors of the urban environment - "the lights, the roads, the cars, the buildings, the cats, the poisons, and everything else" - and it's amazing the Franklin Institute's baby birds have done so well. (At least until growing up and disappearing into the wild blue yonder.)
Then again, no wild bird has the watchful eyes of the Franklin Institute hawks. These birds have been stars of a webcam since they started nesting on the third-floor ledge in 2009.
And every day in recent years, more people come out to gawk at and photograph them.
Last year, when the adult male was killed by a truck on the Schuylkill Expressway, a witness knew about the celebrated hawks and posted on the "Franklin Hawkaholics" Facebook page.
Miraculously, another male arrived and the female accepted him. The nest continued.
On Tuesday, when the third hawk of this year's nest was found injured - the last to hatch and the first to fly; his fans dubbed him Peanut - it was his Facebook following that came to his rescue.
Most of the regulars were elsewhere, watching the empty-nesters - the mother atop a roof near 20th and Callowhill, or the father at 15th and Vine.
Franklin Institute communications manager Sean Tobin spotted the bird on his way to work. He summoned the director of facilities, Mark Harmon, the museum's unofficial liaison with the watchers.
Harmon stood over the injured bird, and, not having phone numbers at hand, posted "hawk down" on Facebook.
Carolyn Sutton was five minutes away. She arrived with heavy gloves and a box - always at the ready in her car.
The East Falls resident is a volunteer with the wildlife rehab center, and every day of nest season, for five years, she has gone downtown by dawn to monitor the birds.
Sutton drove Peanut to the center, where by afternoon he was in a darkened area to keep him calm, awaiting X-rays.
The two birds that flew into Moore windows were less lucky, but the first at least was preserved as a specimen at the Academy of Natural Sciences of Drexel University.
"It might seem strange to have red-tailed hawks as window kills," said collections manager Nate Rice, "but we get virtually every major group of birds," including peregrine falcons, shorebirds, songbirds, woodpeckers, owls, rails, and others.
Moore spokesman Roy Wilbur said the college is planning to install banners featuring students' work in two large windows over the entrance - where they consider collision risk the highest.
"We're just so devastated about the other two," Wilbur said. "We're hoping Peanut is OK."
Contact Sandy Bauers at 215-854-5147, firstname.lastname@example.org, or follow on Twitter @sbauers. Read her blog, GreenSpace, at www.inquirer.com/greenspace.