Officials in Portland voted Wednesday to ban the use of Avitrol, a chemical marketed as a “bird control agent,” which has led to the deaths of dozens of crows on at least two occasions.

In a unanimous vote, commissioners banned use of Avitrol and other chemicals used to deter birds on all property owned and managed by the city.

“These poisons have absolutely no place anywhere in our community,” Commissioner Nick Fish said in a statement. “They not only put our birds and wildlife at risk, but they also put people and pets at risk as well.”

The move comes after two mass die-offs of crows over the last five years. In 2014, scores of dead or seizing birds were reported around the area of Southwest Third Avenue and Columbia. Responders found about 30 dead birds, mostly in downtown parks.

Last year, witnesses in Northeast Portland reported seeing nearly a dozen crows “falling from the sky,” seizing on the ground and dying. At least 10 of the corvids were found dead in the incident, but Bob Sallinger, conservation director of the Portland Audubon Society, said at the time there were likely more deaths than were recorded.

"We're picking up the ones that are easily visible from the street," he told The Oregonian/OregonLive in January 2018. "But we're only able to see a fraction of what's out there. Our concern is that this could be much bigger."

In both 2014 and 2018, testing revealed the birds had all died after ingesting Avitrol. In the earlier incident, responders also took in a gull that fell similarly ill.

Therein lies one of the major problems with Avitrol, critics say.

Described as a “chemical frightening agent” on the Avitrol website, the active ingredient in the product is 4-aminopyridine, which is applied to grain bait and impacts both the central and motor nervous systems, causing birds that ingest it to exhibit behaviors similar to an epileptic seizure. That erratic behavior, according to the company, will frighten the rest of the flock and force the birds to leave the area.

There have been no secondary poisonings from the use of Avitrol, according to the company, which cited a study in which dogs, rats and raptors were fed birds that had ingested the chemical and showed no ill effects. Documents from the Environmental Protection Agency, however, show that “that there is some risk to predators due to secondary effects from” the chemical. The agency noted that there had been four documented animal deaths, at least one of a bird that was endangered at the time, due to ingesting Avitrol.

But that’s an impossible claim to substantiate, Sallinger said, as birds that ingest Avitrol don’t always die immediately. If they die after they fly off, it’s likely they will be eaten by scavengers that may or may not become ill from the poison. If another animal were to die from secondary poisoning, Sallinger said, they would be hard to find and even harder to test for the chemical.

Portland has tried a number of novel approaches to mitigate the crow problem, which mostly boils down to the feculent mess they leave behind when they roost in downtown trees by the thousands in the winter months. They contracted out a Zamboni-like machine called the “Poopmaster 6000” to clean the sidewalks and they employed a falconry company to use Harris hawks to chase the crows to less populated areas.

Some have shown moderate degrees of success. All are better than poison, Sallinger said.

Sallinger conceded that Wednesday’s ban was mostly a symbolic one. The city has never used Avitrol and, had the ban been in place earlier, it likely would not have prevented either of the previous die-offs. But the message sent by the ban is an important one, according to Sallinger.

“It helps put pressure on Avitrol,” he said.”We hope it spreads to other cities so we can move toward other solutions.”

-- Kale Williams

kwilliams@oregonian.com

503-294-4048

@sfkale

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