In case you need further motivation to keep your hummingbird feeders clean, here is a photo of a male Anna’s Hummingbird with a swollen tongue. The condition is caused by a fungal infection, usually acquired at hummingbird feeders. The condition is often, if not always, fatal.
If you feed hummingbirds, please use a mixture of one part WHITE sugar to four parts water, and clean the feeder at least once a week in cool weather, more often when temperatures are warmer. Using any other ingredients, or allowing the nectar to spoil, can be deadly.
This post has received a lot of comments over the years, mostly questions about veterinary care of individual birds and other topics that I am not qualified to answer. If you are a veterinarian or wildlife rehabber, and have insight or advice regarding this condition, please leave a comment. If you are seeking advice about this condition, please contact a vet or a wildlife rehabilitation center.