FAIRBANKS — Twice a year, Marcus Dodge assigns a worker to don disposable coveralls and a respirator for a trip to a downtown Fairbanks parking garage to clean up deposits from a non-native species.
Dodge, director of the Fairbanks Parking Authority, estimates the worker picks up 150 gallons of pigeon dung annually and hauls it to the hazardous materials area at the landfill.
"Pigeon crap weighs a ton," Dodge said. "It's not a lot of fun to clean up."
The downtown pigeon population appears to be growing, according to Dodge and others. Businesses are experimenting with ways to deter the bird, the Fairbanks Daily News-Miner reported.
Roofers last summer discovered 6 inches of pigeon guano on the roof of the Courthouse Square, the former federal courthouse.
Charlie Cole, Alaska's former attorney general, who has kept an office in downtown Fairbanks since 1957, has been talking with neighbors about fending off the birds.
"They leave droppings around warm air outlets where they congregate," Cole said. "I think it's a nuisance."
Pigeon droppings contain ammonia and uric acids that eat away at metal and the sealant on the parking garage concrete floor.
One pigeon can produce 25 pounds of guano per year, according to a government report detailing New York City's pigeon problem. The droppings were cited as possible cause for speeding the decay of a Minneapolis bridge across the Mississippi River that collapsed in 2007 and killed 13 people.
Hunters and dog trainers introduced pigeons to Fairbanks, said Cathie Harms, spokeswoman for the Alaska Department of Fish and Game. The best way to deter them, she said, is to eliminate their food source.
"We are aware that some people are feeding pigeons," she said. "If there wasn't as much food, there wouldn't be as many pigeons."
A maintenance worker for the Springhill Suites Marriott a few months ago tried chasing them off with a recording of predator birds. The sound could be heard from a couple of blocks away and drew complaints from hotel neighbors.
Robert Franklin, a maintenance foreman for JL Properties Inc., which manages the Courthouse Square and the Northward apartment building, calls pigeons flying rats.
"They're a hazard to the equipment. They're a hazard to people," he said. "They get into stuff they are not supposed to."
He uses spike strips and moves owl decoys around to repel pigeons. Success has been mixed, he said.