Birds are consuming alcohol in their diets of fruit and nectar—but in moderation
Several species of birds are regularly consuming alcohol produced by natural fermentation. Researchers tested the amount of ethyl glucuronide (EtG), a byproduct produced when bodies break down alcohol, as a way to estimate the amount of alcohol the birds had consumed. They collected samples from 17 different species of birds donated to the Museum of Vertebrate Ecology in Berkeley, California, and tested feather and liver samples. Ten of the 17 species had EtG in their feathers, while two of the five species had substantial levels of the molecule in their livers. As the researchers anticipated, hummingbirds—which consume mostly sugar-rich nectar, which is ripe for fermentation—often had EtG in their feathers. But EtG was also present in birds with diverse diets, including seeds, insects and animals, indicating that there might be other ways birds are getting alcohol, like through their prey. While a little alcohol may be harmless—or even adaptive in terms of energy consumption—there are also serious risks. “Inebriation may reduce survival and reproductive success, including increased predation risk due to impaired flight performance, injury or death due to accidental collisions during flight, and altered singing behavior,” the authors noted.
Read more in Ecology and Evolutionary Physiology.
