![]() 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. So they’re probably not seeing any real effect. “They burn the alcohol and metabolize it so quickly. “So it’s all consistent with the idea that there’s a natural, chronic exposure to physiologically significant levels of ethanol derived from this nutritional source.” 05% of ethanol you’re getting a substantial load of ethanol relative to your body mass,” he said. But again, if you’re eating 80% of your body weight a day, at. “Now, 0.05% just doesn’t sound like much, and it’s not. When he and his colleagues tested the alcohol level in sugar water that had sat in the feeder for two weeks, they found a much lower concentration: about 0.05% by volume.Ī male Anna’s Hummingbird. “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%.” ‘They’re not getting drunk’ 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. You may not realize it, but that backyard hummingbird feeder filled with sugar water is a natural experiment in fermentation - yeast settle in and turn some of the sugar into alcohol. An Anna’s Hummingbird sipping from a California Fuchsia.
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