![]() "This is the first demonstration of ethanol consumption by birds, quote, in the wild. The new study shows that birds are also likely consuming alcohol produced by natural fermentation. ![]() Another study, published in 2015, found a relatively high alcohol concentration-up to 3.8%-in the nectar eaten by the slow loris, a type of primate, and that both slow lorises and aye-ayes, another primate, preferred nectar with higher alcohol content. A 2008 study found that the nectar in palm flowers consumed by pen-tailed tree shrews, which are small, ratlike animals in West Malaysia, had levels of alcohol as high as 3.8% by volume. No systematic studies of the alcohol content of fruits and nectars, or of alcohol consumption by nectar-sipping birds, insects or mammals, or by fruit-eating animals-including primates-have been done.īut several isolated studies are suggestive. Part of this project involves testing the alcohol content of fruits in Africa and nectar in flowers in the UC Botanical Garden. But that's experimentally tractable," he said. "Does alcohol have any behavioral effect? Does it stimulate feeding at low levels? Does it motivate more frequent attendance of a flower if they get not just sugar, but also ethanol? I don't have the answers to these questions. They seek to understand the role that alcohol plays in animal diets, particularly in the tropics, where fruits and sugary nectar easily ferment, and alcohol cannot help but be consumed by fruit-eating or nectar-sipping animals. The research is part of a long-term project by Dudley and his UC Berkeley colleagues-herpetologist Jim McGuire and bird expert Rauri Bowie, both professors of integrative biology and curators at UC Berkeley's Museum of Vertebrate Zoology. "That was a kind of a threshold effect and suggested to us that whatever's out there in the real world, it's probably not exceeding 1.5%."Ī male Anna’s Hummingbird. ![]() So that was really interesting," Dudley said. "They're consuming the same total amount of ethanol, they're just reducing the volume of the ingested 2% solution. They appear to be only moderate tipplers, however, because they sip only half as much as normal when the sugar water contains 2% alcohol. The results of that study, published this week in the journal Royal Society Open Science, demonstrate that hummingbirds happily sip from sugar water with up to 1% alcohol by volume, finding it just as attractive as plain sugar water. All three of the test subjects were male Anna's hummingbirds (Calypte anna), year-round residents of the Bay Area. Maybe, with feeders, we're not only farming hummingbirds, we're providing a seat at the bar every time they come in."ĭuring the worst of the COVID-19 pandemic, when it became difficult to test these questions in the wilds of Central America and Africa, where there are nectar-feeding sunbirds, he tasked several undergraduate students with experimenting on the hummers visiting the feeder outside his office window to find out whether alcohol in sugar water was a turn-off or a turn-on. But even if there are very low concentrations of ethanol, that volumetric consumption would yield a high dosage of ethanol, if it were out there. ![]() "Most of it is water and the remainder sugar. "Hummingbirds are eating 80% of their body mass a day in nectar," said Dudley, UC Berkeley professor of integrative biology. How much alcohol do hummingbirds consume in their daily quest for sustenance? Are they attracted to alcohol or repelled by it? Since alcohol is a natural byproduct of the sugary fruit and floral nectar that plants produce, is ethanol an inevitable part of the diet of hummingbirds and many other animals? To University of California, Berkeley biologist Robert Dudley, this raises a host of questions. The same is true of nectar-filled flowers, which are an ideal gathering place for yeast-a type of fungus-and for bacteria that metabolize sugar and produce ethanol.
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