When will the cannons operate?
Wednesday, Jan. 14, Friday, Jan. 30 and Wednesday, Feb. 11, 2014 the cannons will be used a total of 3 days for about an hour each day in the late afternoon and early evening. The cannons will not operate on holidays. The cannon firing will end approximately one hour after sunset.
Why do this?
Orchard cannons are a non-lethal
tool that discourages starlings from roosting on the Interstate Bridge.
Every year thousands of starlings
migrate to the Portland/Vancouver area and roost on the Interstate Bridge. Bird
droppings coat the bridge, the catwalks, the roadway, vehicles, bicyclists and
pedestrians. The droppings are acidic and speed corrosion of the steel and are unhealthy,
unsafe, unsightly and unpleasant for workers and bridge users.
How will the bird cannons work?
Propane-powered orchard cannons
were originally designed to disturb birds in apple orchards. They create a loud
noise—the boom of an air cannon—to startle the birds. As many as seven cannons
and as few as one or none have been used The timing and placement on the bridge
varies from year to year.
Each orchard cannon cost
approximately $1,000 and uses about two gallons of propane throughout the hazing.
ODOT will not fire the cannons
every day, but instead will vary the days of cannon use based on the reactions
of the birds. Employing this random schedule prevents the birds from developing
a regular pattern.
Motorists, bicyclists and pedestrians crossing the bridges will hear the blasts, which could occur as often as once every 2-3 seconds.
What else have you tried?
During the past 25 years, maintenance crews have tried virtually everything that seemed even remotely reasonable to purge these pests: noisemakers, loud banging on the structure, chemical applications and sharp-edged moldings, to name just a few.
What is the effec on birds?
The noise from the cannons creates
stress, upsetting their biorhythms and causing them to seek less stressful
places to roost.
When will you know if there’s an effect?
In past years, we noticed an effect almost immediately—birds moved away from the lift spans and settled in nearby trees and on other parts of the bridges further away. This winter we have seen a dramatic reduction in starlings roosting on the Interstate Bridge. In past years approximately 30,000 starlings roosted on the Interstate Bridge. In 2012, ODOT counted 2,000 to 3,000 starlings roosting.
What’s the best result you can hope for?
We would prefer the birds move off the bridges completely. Realistically, though, significantly reduced numbers on the lift spans is ODOT’s goal. Obviously the lift spans play a crucial role for both Interstate 5 traffic and marine traffic. Ensuring the bridges operate smoothly and that ODOT personnel are able to work in a safe and healthy environment is our paramount concern.
loud are the cannons?
noise level of the cannons is similar to the noise level of vehicle traffic on
the bridge. When firing, the orchard cannons noise level is 95 decibels.
Traffic on the bridge is 90 decibels; a jet flying over the bridge is 100
pedestrians and bicyclists using the bridge will hear the blasts. People who
live or visit businesses near the bridge will also hear the blasts.
Are there warning signs?
Yes, warning signs will be posted at all entrances to the sidewalks to notify bicyclists and pedestrians of the noise.