I've never seen any other unintended critter (besides ants) get on my feeders, which are cleaned every day & fresh nectar put in while I'm making coffee. It's around 95 here every day. They're never empty but I change it anyway. If the nectar sours, it can start to have alcohol in it, which is not safe for hummers.
This article has some great info. Pasting some below but there's so much more:
http://www.hummingbirdmarket.c...
Changing Hummingbird Nectar
- Nectar feeders in full sun may spoil more rapidly than those which are shade protected.
- Exposed to heat and the sun sugars can ferment and turn to alcohol, it can evaporate and alter the sugar/ water concentration ratio, or bacterial growth can begin.
- Change nectar often to prevent such fermentation and mold or bacteria build-up. Twice a week is highly recommended in general. Particular circumstances, such as extremely hot or cold daily temperatures, may determine a longer or shorter โfreshness timeโ for nectar. Fermented nectar (left out too long) is giving your hummingbirds a license to fly drunk. Avoid this happening by keeping a regular schedule for cleaning and refilling.
- Adult hummers know not drink spoiled nectar and their little internal GPS system will alert them to avoid that contaminated feeder. Changing your nectar solution as recommended will prevent juveniles, who are not as seasoned or experienced as adults, from drinking harmful nectar.
Cleaning Hummingbird Feeders
- Avoid using soaps, bleach, or chorines when cleaning your feeders between refills. Using hot water and a brush/sponge will leave no residues. Rinse well!
- A 50/50 dilute solution of vinegar is a good cleaning method for removing mold. But rinse well.
- Feeders need to be cleaned, and nectar changed every 3-4 days--more often in hotter weather.
- If you see black spots inside your feeder this is mold and you will need to scrub it out with a good bottle brush, but if you can't reach it with a bottle brush you can add some sand with water and shake the feeder to remove the mold.
- Don't fill the feeder more than half full if they can't drink it all before it needs to be changed.
- If you notice that the nectar is turning milky or that white strings or black spots are growing in it, change it more often. Clean the feeder with very hot water each time you refill it.
- Most good feeders, and all of of the ones that we sell, come apart for easier cleaning. Be sure and take them apart every time. It is usually the work of a couple of seconds.
- If contamination occurs, use a mild vinegar solution to sterilize it, but if you opt to use bleach, rinse thoroughly afterwards. Even a tiny amount of bleach could be harmful to birds weighing only a few grams!
- Glass or metal pieces can be boiled, but you should probably not boil plastic pieces.
- All of the high quality pan/ saucer type of feeders constructed of UV stable polycarbonate can safely be cleaned on the top rack of your dishwasher. The durability of this type of material guarantees many years of use without any warping, bowing or distortion of the feeder.
