Birds and Bees Sip Alcohol From Flower Nectar

Study finds detectable alcohol levels in nectar of 26 out of 29 plant species tested

Mar. 26, 2026 at 4:34am

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A new study from UC Berkeley biologists has found that flower nectar often contains detectable levels of alcohol, with some samples containing up to 0.056% ethanol by weight. This means that nectar-feeding animals like hummingbirds and bees are regularly consuming small amounts of alcohol as part of their diet. While the alcohol levels are low, the researchers say the chronic exposure could have physiological effects on these animals that deserve further study.

Why it matters

This study provides new insights into the ubiquity of dietary alcohol consumption in the natural world, challenging assumptions that the physiological responses to alcohol seen in humans may not be representative of all animals. It suggests there could be a range of adaptations across species to handle regular, low-level alcohol intake from their food sources.

The details

The researchers analyzed the nectar of 29 plant species and found detectable alcohol levels in 26 of them, with one sample containing 0.056% ethanol. They estimate that nectar-feeding animals like hummingbirds and sunbirds could be consuming 0.19-0.27 grams of alcohol per kilogram of body weight per day when feeding on flowers native to their habitats. This is comparable to a human having one standard alcoholic drink per day. While the animals don't appear to show obvious intoxication effects, the researchers say the chronic exposure could have other physiological impacts that deserve further study.

  • The study was published on March 25, 2026 in the journal Royal Society Open Science.

The players

Aleksey Maro

A UC Berkeley doctoral student who collected and analyzed the nectar samples.

Ammon Corl

A UC Berkeley postdoctoral fellow who worked with Maro on the nectar analysis.

Robert Dudley

A UC Berkeley professor of integrative biology who oversaw the research project.

Rauri Bowie

A UC Berkeley professor of integrative biology and curator at the Museum of Vertebrate Zoology, who co-authored the study.

Jimmy McGuire

A UC Berkeley professor of integrative biology and curator at the Museum of Vertebrate Zoology, who co-authored the study.

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What they’re saying

“Hummingbirds are like little furnaces. They burn through everything really quick, so you don't expect anything to accumulate in their bloodstream.”

— Aleksey Maro, UC Berkeley doctoral student

“There may be other kinds of effects specific to the foraging biology of the species in question that could be beneficial. They're burning it so fast, I'm guessing that they probably aren't suffering inebriating effects. But it may also have other consequences for their behavior.”

— Robert Dudley, UC Berkeley professor of integrative biology

What’s next

The researchers plan to continue studying the physiological and behavioral effects of chronic low-level alcohol consumption in nectar-feeding animals like hummingbirds and sunbirds.

The takeaway

This study challenges the assumption that the physiological responses to alcohol seen in humans are representative of all animals. It suggests there may be a broad range of adaptations across species to handle regular, low-level alcohol intake from their food sources, with potential implications for understanding the evolution of alcohol tolerance.