The Oregon Department of Transportation on Thursday began deploying propane-powered air cannons in its annual war against starlings on the Interstate 5 Bridge.
ODOT crews installed two cannons this year, intended to scare away the birds that come by the thousands each year and roost on the bridge, particularly its lift spans. The cannons will operate on 12 days between now and March 16, firing for about two hours each day in the late afternoon and early evening, according to ODOT.
Blasts, which are audible to motorists, residents and workers closest to the bridge, will occur as often as once every 15 seconds. Crews will fire the cannons on a random schedule to keep the birds from becoming accustomed to a regular pattern, according to ODOT.
ODOT began using air cannons to deter starlings in 2003. The birds' droppings are unsafe and unhealthy for bridge workers, and can also corrode the structure itself, according to the agency.