By Bob Sargent
Based on 30 years of studying and banding wintering hummingbird species in the eastern United States, here are my recommendations for preventing the contents of hummingbird feeders from freezing.
My personal recommendation is to continue to fill your feeders with the widely accepted mix of four parts water to one part regular table sugar (4 to 1). A mixture of 3 to 1, water to sugar is probably not harmful but it may lead down that slippery slope of ever-stronger mixes that probably are not useful and may in fact be less than desirable for hummingbirds. Note that a 4 to 1 ratio mix begins freezing when the temperatures drop to the 26-27 degree Fahrenheit range. At and below these temperatures, the fluid will likely become somewhat slushy. Hummingbirds will still feed on slushy sugar water at temperatures even lower.
One option to prevent freezing is bring the feeder in at night and put it out again before dawn the next morning. While this works fine if you are a dedicated, stay-at-home early-riser. This system is, however, full of dismal failures, such as sleeping late, forgetting, sickness, vacations etc, plus the feeder will promptly freeze again as soon as it is placed outside on mid-20s or lower mornings. Needless to say this is not my favorite option.
The most successful option is to use a 150-watt outside flood or spot lamp in a clip-on utility light fixture. The lamp needs to be one of the shatterproof lamps like those that most of us have under the eaves of our homes. The glass on these “bulbs” is usually a Pyrex-type glass. They will not shatter when they are hot in cases where cold rain or snow splashes on them. The fixture is a handyman type, with 8” to 12”aluminum reflector with a lamp socket in the center of the reflector. The reflector will swivel to adjust the angle of the lamp. It should be equipped with a 6 foot long plug-in cord. The fixture has a spring handle that opens the gripping jaws when squeezed. The jaws will close allowing the fixture to close on many different surfaces when your grip is released on the handle. The spring-loaded jaws will affix easily to a shepherd’s hook, deck railing, hanger wire, plant arbor, any protruding wood or metal surface etc. I recommend that the face of the “heat lamp” be placed so that it is 10” to 12” from the feeder “bottle”. This arrangement can easily be turned on and off at the fixture or by unplugging the cord. If you use an extension cord to reach the “pigtail” cord on the light fixture, I suggest that you plug the fixture cord into your extension cord, and then place that connection in a Ziploc type baggie and tape it closed to make it more waterproof.
Finally, another method you may wish to try is to use a 3-foot long plumber’s heat tape. These flexible electric tapes resemble a flat extension cord and can be easily wrapped and taped to many types and shapes of hummingbird feeders. Most heat tapes are equipped with a built-in thermostat in the cord that will energize when the air temperature approaches 40 degrees F. The wattage on these tapes is very low and the cost of operation is minimal.
Good luck and happy hum-feeding!