It's a case fit for wildlife CSI: 55 robins from the Mount Tabor neighborhood -- all dead within a few nearby backyards.
Toxic spill?
Mystery virus?
Maybe not. The leading theory is that the birds were fatally intoxicated, said Bob Sallinger of the Audubon Society of Portland's wildlife care center, where the birds ended up last week.
That's right: The birds drank themselves to death.
Not from a bottle, though. The birds' bellies were chock full of holly berries, skins and seeds. Sallinger isn't dismissing other explanations yet, but the current thinking is that the birds ate aged and fermented berries that killed them.
Lethal doses of ethanol may have formed in the berries as natural sugars fermented over the fall and winter.
Holly berries are not a prime robin food, Sallinger said, but the birds could have turned to them as a last resort when last week's icy weather froze the ground and made it tough to dig for worms or other, tastier meals.
The robins travel in flocks this time of year, so they could have gobbled the berries together last week. They may have died from ethanol poisoning directly or dropped into such a stupor they died of exposure.
"Certainly a drunk bird in the rain is pretty vulnerable," Sallinger said.
Bird intoxication is not unheard of. It's common in fall for the Audubon care center to get disoriented cedar waxwings that have feasted -- though not fatally -- on fermented berries.
"They come in, and they're hammered," Sallinger said. "We give them a day or two to sober up, and then we send them on their way."
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