Scientists have found that drunk birds slur their songs, just like humans do when intoxicated. Researchers said that speech impairment is one of the least understood and most intriguing effects of alcohol on cognitive function. Christopher Olson and his colleagues at the Oregon Health and Science University found that Zebra finches slur their song when drunk.
Alcohol affects acoustic features of birdsong
Researchers chose Zebra finches for the study because they are a representative of songbird species. These birds learn to sing the same way humans learn speech. Scientists gave white grape juice to one group of birds, and a mixture of juice and 6% alcohol to another group. They found that Zebra finches would consume alcohol when presented to them, causing an elevated blood ethanol content (BEC).
Birds in the first group behaved normal. In the second group, alcohol did not visibly affect the Zebra finches’ general behaviors, motivation or willingness to sing. Even variability of the vocal output was unaffected. But alcohol affected acoustic features of birdsong, particularly amplitude and entropy. The birds failed to keep their learned song’s normal structure stable, and they were unable to sing as loudly.
Birds showed no major effect on their general behavior
Olson said birds became less organized in their sound production. Certain syllables sounded different when the Zebra finches were under influence, likely “reflecting a diversity in the neural mechanisms.” Their general behavior was pretty normal. Drunk Zebra finches didn’t fly around willy-nilly, unlike humans who are unable to walk in a straight line under influence. Birds suffered no closed eyes, no drooped wings, and no sluggishness.
Findings of the study were published in the journal PLOS ONE. The study could help researchers learn more about the effect of alcohol on the human brain and learned social behaviors, thanks to the parallels between human speech and birdsong. Zebra finches could serve as a powerful animal model for understanding the mechanisms underlying vocal learning and production.