I don't have a lot of hummers here. The population density in the desert is low. They are extremely territorial and will guard a feeder, so I never see more than one at a time. Some species live here all year. I have two feeders on two sides of the house so they cannot be seen at the same time.
I only fill my feeders about a quarter full, because that is all the birds drink in a week. I don't get mold if I change the solution weekly. I usually do it Sunday night while I'm planning the next week. People whose birds empty the feeder quickly don't have to worry as much about mold in the feeder.
I do my cleaning and refilling at night so I don't interrupt their feeding. I too prefer glass jars. I don't recommend plastic; they are much harder to clean and sanitize. I have a Perky Pet Pinch Waist feeder. I also have a very old feeder with a globular plastic jar.
I boil water in the microwave in a large glass measuring cup. I add the sugar after the water is boiling, stir to dissolve, and bring it back to a boil. I use 3 parts water and 1 part sugar. If I'm preparing more than I'm going to use to fill the feeder, I pour the boiled sugar water into a canning jar with a sealing lid, put the jar in the microwave, and bring it back to a boil. I then set the lid on the jar, let the air inside and the lid get really warm, and screw on the lid. I let it cool on the counter, then put it into the refrigerator. I have forgotten sugar water jars for months in the refrigerator and there is no mold growth.
If I am using refrigerated solution I open the jar, pour it into a glass measuring cup, and reboil it in the microwave.
I rinse my bottle well with hot water, then put 2-3 tablespoons / 30-45ml of water inside. I put it in the microwave sideways until it boils for 45-60 seconds. I have a rotating platform in the microwave so all surfaces of the bottle are exposed to steam. I can't do this with the plastic jar feeder, which is why I wouldn't buy one again.
I remove the feeder jar with a hot mitten, empty it, and fill with hot sugar solution I've prepared. This is one of the reasons I boil the sugar solution in a measuring cup: It makes it easier to pour into the feeder jar. I set the filled jar on the rack in my cold oven to cool, so there is minimal air disturbance around it, which might blow mold spores into the open jar. When it is hand-warm I screw on the plastic feeder base and put it back outside.
If I change the solution weekly, there is no mold. If I let it go longer there may be black mold inside the feeder. If this happens I rinse with a 10% bleach solution and let it sit for 20-30 minutes, shaking it frequently. Then I rinse it very well.
If the feeder is in the sun, as the air in the feeder cools down after sunset, it shrinks in volume. Air is sucked into the feeder. The next day, as the air is heated by the sun, it expands and pushes sugar solution out of the feeder. Your feeder will always drip if it is in the sun, unless your birds drink the solution so fast this can't happen. My hummers start feeding before daybreak.
As mentioned before, I put mineral oil or petroleum jelly on my hanging wire to keep ants off the feeder. I haven't had problems with bees finding the feeder, but this happens sometimes. They sell plastic baskets that fit over the feeder spouts; the bees can't reach the spout, but the hummer can.
The
Arizona-Sonora Desert Museum in Tucson has a hummingbird aviary with many species.
If you're ever in Orange County, California, be sure to visit the
Tucker Wildlife Sanctuary in Modjeska Canyon. They have dozens of feeders for many hundreds of hummers.