Unless there’s some evidence I’m not aware of, we’re at the same stage with honey that we were with red dyes before all the good studies came to light: stuck with Nancy N.’s mantra of unnatural, unnecessary, and potentially harmful – all perfectly good reasons to avoid it, though not as compelling as DNA damage, developmental toxicity, and aggravation of ADHD symptoms.

I’ve also used infant botulism as a cautionary example of the dangers of honey, but on closer scrutiny the evidence at hand for its impact on hummingbirds seems far less compelling than that for “tongue fungus” (which is almost certainly candidiasis). I say “at hand” because some of the red dye papers were several years old before I stumbled onto them, so it’s possible that there’s some research out there that relates to botulism as a hazard for hummingbirds.

In the absence of evidence, I had to ask myself: Is it justifiable to assume that normal, healthy hummingbirds are as vulnerable to botulism as human infants? Is there something about their biology that would make them more susceptible than older humans, whose digestive acids destroy the spores or intestinal flora outcompete the bacteria? I think the answer is no. In fact, I wonder if their high food intake and rapid digestive turnover rate compared to humans and other birds would help to inhibit the growth of C. botulinum by maintaining relatively aerobic conditions in the gut?

The other possibility is that the bacteria grow in the feeder and poison the solution. Again, this may be an unlikely scenario considering that they need anaerobic conditions to flourish. Still, it would be interesting to compare the flora that grow in a honey solution vs. sugar water and look specifically for C. botulinum and other potential pathogens. (Is there a microbiologist in the house??)

Another issue is that the spores are everywhere, not just in honey. According to the California Department of Health Services Infant Botulism Treatment and Prevention Program: “By a process of exclusion (testing over the years of hundreds of foods, beverages and other items placed in infants’ mouths with negative results), it was concluded that most infant botulism patients acquired their spores by swallowing microscopic dust particles that carry the spores.” So hummingbirds will be exposed to C. botulinum spores no matter what we put in our feeders, but it still falls to us to avoid doing anything that would increase the risk of disease associated with that exposure.

Here’s an in-depth review of botulism from the Wildlife Center of Virginia, and I’ve just sent a reprint request for an article on captive maintenance of hummingbirds and sunbirds in hopes that it will shed some light on the “tongue fungus” issue.

Thanks for reading LB&E and keeping me on my toes!