[Micmac]

Greg,
We also have a feeder, and I had never heard of what Special-K was talking about so I turned on the google machine and found this.

If mold and fungus grow in the feeder, the fungus can infect the hummingbird's tongue and make it swell up causing the condition known as Hummers Candidiasis.

You can use a bleach solution (made from 1 part bleach to 9 parts water) or a vinegar solution (1 part vinegar to 2 parts water). Make sure you rinse all parts thoroughly with clean water before refilling them. You'll need to clean hummingbird feeders more frequently than other feeders.