Drivers and neighbors may hear the blasting sounds of two propane air cannons on the Interstate Bridge connecting Portland and Vancouver over the next two months.
Oregon Department of Transportation planned to start firing the cannons today to scare invasive and meddlesome starling birds off the spans of the bridge, where they roost and drop feces this time of year.
Their droppings coat the bridge, catwalks, roadway, vehicles, bicyclists and pedestrians, creating an unhealthy, unsafe and unsightly situation, according to ODOT. The cannons, sometimes fired as often as once every 15 seconds, make a loud boom to startle the birds, according to ODOT spokeswoman Kimberly Dinwiddie.
She said the hazing has significantly thinned out the number of starlings roosting on the bridge in recent years from 30,000 birds to roughly 3,000 this year.
Workers will vary the intervals at which the cannons are fired so the birds don't get accustomed to the blasts. Crews will wait until evening after the birds are done feeding to fire the cannons, Dinwiddie said. That way, they burn through their food supply when they flee the blasts and end up roosting closer to a food source – not on the bridge.
Starlings a notorious invasive species in Oregon and across the country, according to Rick Boatner of Oregon Department of Fish and Wildlife. The European invaders are aggressive and have been known to kick other birds out of their nests. They eat tons of food, swarming farms, food lots and dairies and dropping feces that can spread diseases to livestock, he said.
"They're a big nuisance," said Boatner. "They spread all the way across the country in such huge numbers that you're not going to eradicate them. You just control them the best you can."
The U.S. Department of Agriculture's Wildlife Services has some tactics for shooting the birds with shotguns, trapping them and poisoning them, Boatner said. And because they are considered predatory, non-migratory birds in Oregon, the state puts very few restrictions on what people can do to kill them.
"Basically, you can do anything you want to them as long as it's legal in the county or the city you live in," he said.
There are only three other birds that bear that classification in Oregon: house sparrows, rock doves (i.e. pigeons), and Eurasian collared doves.
I've written about the prospect of people eating starlings, in addition to other invasive species, in order to reduce their numbers. If you're interested, I suppose now you know where to find some!