Flower nectar contains alcohol. Not trace amounts in rare cases — a UC Berkeley survey found ethanol in at least one sample from 26 of 29 plant species examined. Yeast ferments the sugars, just as it does anywhere sugar and moisture meet. The alcohol is ubiquitous.
Hummingbirds drink between 50% and 150% of their body weight in nectar daily. At the ethanol concentrations measured, an Anna's hummingbird consumes roughly 0.2 grams of ethanol per kilogram of body weight per day — the human equivalent of about one drink. They show no signs of intoxication. No staggering, no impaired flight, no reduction in territorial aggression or mating displays. They fight, court, preen, and navigate precisely, all while consuming what would noticeably affect a human.
The mechanism is metabolic throughput. Hummingbirds burn fuel at extraordinary rates — their metabolic rate per gram of body mass is among the highest of any vertebrate. They process the alcohol as fast as they ingest it, converting it to energy before it accumulates enough to impair neural function. The tolerance isn't behavioral adaptation or learned resistance. It's a side effect of being a metabolic furnace. When your baseline energy expenditure is extreme, low-concentration toxins get burned as fuel before they reach effective concentrations.
The structural point: what looks like a toxin at one metabolic rate becomes a nutrient at another. The same molecule (ethanol), at the same dose per body mass, has completely different physiological meaning depending on how fast the organism processes it. The substance doesn't change. The metabolic context determines whether it's a poison or a calorie. Alcohol is only a drug when the metabolism can't keep up with the intake.
Twenty-six of twenty-nine species. The pollinators have been drinking all along.