BY LEAH GRABOSKI
Published March 13, 2006
If you noticed less music around Central Campus last week, you weren't alone. Two peregrine falcons have silenced the hourly bells on Burton Memorial Tower.
The falcons, which are quickly becoming the most talked-about birds in Ann Arbor, were spotted Wednesday perched on the highest ledge of the 70-year-old tower.
While on a lunchtime stroll, Jacco Gelderloos, a member of the Washtenaw Audubon Society - an organization that promotes the protection of birds within the county - first spotted one of the falcons circling the tower.
Peregrines are the fastest animals in the world. During dives, they have been known to top speeds of 200 miles per hour. In the 1960s, peregrine falcons were near extinction and could not be found anywhere east of the Mississippi River.
"For most of my life, these birds were basically legendary phantoms," Dave Sing, a student in the School of Natural Resources and the Environment, said in an e-mail interview.
Experts believe the bell tower's newest residents are the first of their kind - there are no documented cases of Peregrines nesting in Ann Arbor.
It is not yet clear whether the birds are nesting in the bell tower, but bird experts believe it is highly possible.
"There is strong evidence that the falcons are nesting," said Ray Stocking, president of the Washtenaw Audubon Society. "We know there are two. We've seen the courtship dance. We've seen them fend off crows. This is not proof, but it is encouraging."
Bradley Bloom, associate dean for administrative affairs at the School of Music, decided to stop the chimes at Burton Tower because "one of the society's members observed that the hourly striking of the bells caused the birds to fly away."
Steven Ball plays the tower's bells, which are actually part of an instrument called a carillon. He said of the birds' arrival: "I couldn't be happier because it has generated an enormous amount of interest in the carillon."
But don't worry about getting attacked - the birds are almost oblivious to humans, Sing said.
"They don't care if the bells ring or not," he said. "They selected the site and were using it when the bells were ringing."
Forty years ago, peregrine falcons were considered endangered because of the widespread use of DDT. DDT, a banned insecticide once used in fertilizer, made its way through the food chain. When the insecticide reached the falcons, it had a particularly harmful side effect: their eggshells became so thin that they cracked when the parents sat on them during incubation.
Since the banning of DDT in 1972, the falcons have made a comeback, adapting especially well to urban areas, English Prof. Macklin Smith, an experienced bird watcher, said in an e-mail. Peregrines were taken off the federal endangered species list in 1998.
Smith said he does not think Ball should stop playing the carillon.
"When peregrines became to come back to the east coast, in New York City, they first occupied bridges," he said. "Think about all the honking, and think about the vibrations from traffic. An occasional carillon melody might seem comparably pleasant."
If the birds are nesting, they will stick around for at least another two months, Stocking said.
Smith said the peregrines' nesting might have some unwanted side effects.
"For one thing, there will be pigeon carcasses dropped onto the pavement below," he said, citing the way peregrines dispose of their food after eating. peregrines attack pigeons mid-air, often swooping from tall heights to catch their prey.
University administration should continue to be respectful of the birds' presence, Stocking said. This includes avoiding human contact and not interfering further with the birds.
Scientific name: falco peregrinus
Falcons' fastest recorded speed: 242 mph
Preferred nesting site: High cliffs
Favorite food: Smaller birds
Incubation period: 32 to 35 days