New research suggest birds have trouble singing and calling after a few too many drinks. That's right, drunk birds slur their words.

As part of a massive effort to plot the most extensive avian family tree, researchers decided to test the effects of alcohol on communication skills. Because zebra finches are often used to better understand vocal learning in humans, scientists at Oregon Health and Science University chose the species as their barroom test subjects.

"We just showed up in the morning and mixed a little bit of juice with 6 percent alcohol, and put it in their water bottles and put it in the cages," researcher Christopher Olson told Arun Rath on NPR's All Things Considered.

"At first we were thinking that they wouldn't drink on their own because, you know, a lot of animals just won't touch the stuff," Olson said. "But they seem to tolerate it pretty well and be somewhat willing to consume it."

Olson and his colleagues found that just the slightest of buzzes altered the characteristics of the birds' calls and songs. Their chirps became a bit fainter and just a bit slurred.

The sounds of drunk birds may not be isolated to the laboratory. Research in Canada showed that waxwings in the Yukon can sometimes get sauced by consuming a few too many fermented berries as fall turns to winter.

"Most birds likely just get a bit tipsy, and very few people would be able to pick them out as intoxicated," Meghan Larivee, a researcher at government agency Environment Yukon, told National Geographic. "However, every now and then, some birds just overdo it."