The 1,000 or so double-crested cormorants that used to coat the Wrightsville Beach, NC, drawbridge with their corrosive droppings have been dispatched—with a bang.
So have their feathered brethren at Surf City, NC. The North Carolina Department of Transportation, fed up with the cormorants leaving a mess on the towns’ bridges (not to mention nearby parks, marina and homes), have recently turned to a pyrotechnic called “Bird Bangers” to rid the towns of the birds.
Bird Bangers, similar to firecrackers, are fired from a specially designed pyrotechnic gun into the air—away from the birds. The cartridge explodes with a loud bang about 100 feet away, driving the birds to find an alternative roost, experts say.
‘We Bother the Birds to Move On’
“This is a non-lethal way to encourage the cormorants to find another roost,” said Amanda T. Glynn, PE, division bridge program manager for NCDOT. “The basic principle is that we bother the birds enough to move on. Hopefully, it will convince them there are more hospitable places for them to roost.”
The project has been a cooperative effort by NCDOT, which owns the bridges; the two towns; and the U.S. Department of Agriculture’s division of wildlife services.
The state and the towns have been searching for years for a way to safely disperse the cormorants, which roost by the hundreds on power lines over the town bridges.
“There will be as many as 1,000 at a time over the park and marina,” said Wrightsville Beach town manager Bob Simpson. “It just inundates with their droppings. It’s like snow.”
A series of dry winters with little rain to wash away the chronic mess hasn’t helped, causing a major maintenance challenge, Simpson said. Residents complain about the smell (Simpson called the aroma “significant”), and DOT is concerned about the integrity of the bridges.
“It was pretty significant all over the bridges,” said Glynn. “It was eating the bridge steel.” Intensive maintenance has prevented damage to the integrity of the bridge so far, she added.
Last but not least, Simpson said, birds were getting zapped on the power lines, and the town regularly had to dispose of carcasses.
A Blessing with a Bang
Surf City, NC, successfully used four or five rounds of Bird Bangers last fall to disperse the birds from its swing span bridge, and Wrightsville Beach is finding success after just one round, said Jordan Miller, a wildlife services specialist with USDA. Miller helped design Surf City’s program and was the “bird banger” on the ground who fired off about 30 of the explosives last week, to send the cormorants of Wrightsville Beach packing.
A weekend check of the site, several days after the rounds were fired, found no birds, Miller said. Two birds eventually landed on the wires but then flew off. “Without the numbers there, they’re not going to consider it a safe roost site,” he said.
Simpson has noticed the difference, too. He used to see 300 to 800 birds on the lines during his morning and evening commutes, he said, and he has not seen one since last week.
“It was kind of a blessing, because we’ve been dealing with it every winter season,” he said. The town tried to see if the power company could put up some special line to discourage the birds. When that didn’t work, officials met with someone who said he could generate sound waves to drive off the birds, “but he wanted $10,000 and that wasn’t happening.”
‘A Sensitive Issue’
The Bangers seem “to have been very effective,” Simpson says. The state and town “took a lot of grief from the local press and the environmentalists. But it doesn’t do any damage to the birds. It really did work.”
Miller, of USDA, will be monitoring the outcome for his agency and DOT. If the birds return—which can happen if there is no suitable alternative roost—another round may be in order.
Miller said Wildlife Services had successfully used bird-dispersing pyrotechnics across the country. Although it is a low-cost, effective method, he warns that the products are strictly regulated and, like any gun or explosive, can cause harm if mishandled.
The U.S. Bureau of Alcohol, Tobacco and Firearms requires that users complete a Wildlife Control Statement before purchasing Bird Bangers, and the product is shipped as hazardous material.
“It seems like a real simple task and it can be, but it’s a sensitive issue,” said Miller. “The nice thing about this kind of project is that it’s a cooperative effort. We’ll work together and see what happens.”