November 4, 2012
Fermented Berries Can Cause Young Birds To Get Drunk
redOrbit Staff & Wire Reports - Your Universe Online
A dozen dead blackbirds, discovered last summer by officials in northwestern England who feared they had been abused, had actually sustained their fatal injuries after getting drunk on fermented berries.
"The sick bird was taken to a wildlife rescue center where staff said it was unsteady on its feet and rested both wings on the ground to support itself while leaning against the wall of its enclosure," Smith explained. "They said it appeared 'drunk'. It made a full recovery and was released two days later."
The other 12 birds underwent post-mortem examinations at the Animal Health and Veterinary Laboratories Agency (AHVLA), she said. Each was tested for avian flu and other diseases, but those tests came back negative. Some of them did show signs of traumatic injuries, and all of them had berries in their bellies -- berries which Smith said smelled as though they had become fermented.
The AHVLA researchers, who published their findings in the journal Veterinary Record, said in a prepared statement by the British Medical Journal that some of the blackbirds had been seen on rowan trees, and berries similar to those found in the birds' stomachs, some of which appeared to have been partially consumed, were found on the ground around those trees.
Rowan berries are not poisonous to wild birds under normal circumstances, but considering the odor of those that had been found in the birds' systems, three tissue samples were sent for toxicological analysis. One of them tested positive from high levels of pure alcohol (ethanol).
"The authors can't explain why only one of the samples revealed the presence of ethanol, but suspect that all the dead birds had become intoxicated on fermented berries, and that some of the injuries they had sustained were the result of mid-air collisions," the statement explained. "The berries on the ground were damaged, so would have been vulnerable to yeast infestation, which would have precipitated fermentation and subsequent alcohol production, they explain."
"The authors say that they can't prove that the birds died after consuming too much alcohol, but they refer to a similar diagnosis made in 1999 of redwings who had been feeding on holly berries," it added. "Several of these birds were seen falling out of the holly tree onto the concrete below. Laboratory analysis did not reveal any hazardous chemicals, but holly berries were found in their crops and gizzards, samples of which contained high levels of alcohol."