Just like the drunk at the local karaoke bar, birds slur their songs too when they are under the influence. Researchers from Oregon Health & Science University recently reported in the journal PLOS One that birds intoxicated with alcohol exhibit impaired singing, much like their human counterparts attempting to speak while under the influence. The research, the scientists say, provides new insights into the neural underpinnings of songs in birds and speech in humans.

Zebra finches are a species of bird that scientists often use in the study of the origins of language among humans. The finches exhibit similar learning patterns as observed in humans. For example, they learn to make complex sound sequences by listening to others around them, much the same way humans seem to learn language.

“There are remarkable analogies in how zebra finch song and human speech are learned and produced,” the authors of the study wrote.

There are some differences, however. For one, only male zebra finches sing. The researchers fed white grape juice to a control group of male birds and the same juice laced with ethanol to another experimental group. Then they studied the songs emitted by the two groups of finches to find differences associated with the ethanol consumption.

In the group that consumed ethanol-laced juice, the amplitude and entropy of the songs were altered, compared with those of control group birds. The intoxicated birds could not sing as loudly, nor could they maintain their song structures. Interestingly, not all song characteristics were altered.

In addition, the intoxicated birds did not exhibit alterations in posture or appearance. They did not let their wings droop or eyes closed, nor did they appear sluggish. In other words, they did not look drunk.

“We did not detect visible effects on the birds’ general behaviors or health, as indicated by the normal appearance of feathers and the ability to perch, feed, maintain normal posture and fly inside the cage,” the authors reported.