Hummingbirds prefer clean feeders.
image by michael hatherly: sxc.hu
One way to get a close-up look at hummingbirds is to hang a hummingbird feeder filled with sugar-water "nectar." The hummingbirds will then visit your feeder for a tasty treat throughout the day. Due to the high sugar content of the nectar, the feeders are prone to mold and mildew growth. This can be fatal to hummers, so proper sanitizing is a must. Feeders should be sanitized before refilling or whenever mold growth is discovered. A clean feeder and healthy hummingbirds lead to more visits from these quick little birds.
Choose a feeder that is easy to clean. Ensure that you can access every part of the feeder's insides with a bottle brush or other scrubbing tool.
Clean the feeder when it is empty or every three days---whichever occurs first. Check the feeder daily for cloudy water or mold growth, and clean it immediately if either are present.
Empty any excess nectar from the feeder. Flush out the bottle or basin with hot water, and pour hot water through the drinking tubes and mesh.
Remove any dirt or nectar residue with a bottle brush or dish scrubber. Clean all parts of the feeder.
Sanitize your feeder monthly. Mix 1/4 cup of bleach with 1 gallon of water, and soak the disassembled feeder in the solution for one hour.
Wash the feeder with a bottle brush, then rinse it thoroughly with running water. Let the feeder dry completely before refilling.