Why You Might See Someone Putting Aluminum Foil On Their Hummingbird Feeder

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You might have seen your neighbor wrapping aluminum foil around their hummingbird feeders. Understandably, you may wonder, "Why in the world would they put aluminum foil on their feeder?" While a bit odd at first glance, they are simply trying to keep the nectar (the sugar mixture) in the feeder from overheating and degrading in a way that could harm hummingbirds. The obvious next question is: can that happen? The short answer is yes. In very hot weather, the sugar mixture in hummingbird feeders may grow bacteria or mold harmful to these little birds. The tin foil is an attempt to keep that from happening.

You may not know what to put in your hummingbird feeder. The answer is a sugar-water mixture at a 4:1 ratio of water to sugar. According to the Smithsonian's National Zoo & Conservation Biology Institute, there is no need to boil it. Instead, make sure the sugar water is well mixed. While you do not need to boil the mixture, if you do, it can help the sugar to be fully absorbed. Plus, it also kills potential bacteria in the water. 

Once in the feeder, hot weather can speed up bacteria and mold growth. Generally, you should empty and refill your hummingbird feeder at least twice a week in warm weather to prevent bacteria and mold from growing. You'll also need to clean the feeder at least once a week, because not cleaning your feeder can be deadly to the birds. Luckily, you may be able to use aluminum foil as a hack to prevent the nectar in your feeder from overheating, which could possibly slow or reduce bacterial growth.

People who wrap their hummingbird feeder with aluminum foil are doing so in hopes that it will reflect sunlight and its heat. Aluminum is curious and can reflect sunlight, effectively limiting its solar energy transfer. Aluminum has a high rate of thermal conductivity, which means it can transfer, dissipate, and conduct heat exceptionally well. By wrapping the feeder in foil, the goal is to bounce that energy away rather than letting it be absorbed as heat. It will certainly help in this regard. But without scientific backing that this aluminum hack works specifically for hummingbird feeders, there are other steps you can take to keep your nectar cooler.

In super-hot weather two basic things will help the most; first, move the feeder into a full-shade area. This common-sense move will be a big help. Second, change the nectar daily rather than weekly or bi-weekly, which will ensure it stays at a healthy temperature. One more possibility to protect the nectar is to use a store-bought glass feeder, like this More Birds red jewel option. You could also save your old glass jars to DIY a simple hummingbird feeder on a budget. Glass keeps the nectar cooler than plastic will. 

And while it will not cool your nectar, birdbaths and water misters can help cool the hummingbirds themselves. Hummingbirds can survive tropical conditions, but those of us helping to feed them need to take steps to keep their sugar-water solution safe. A little more attention to your feeder during hot weather using methods to keep the nectar from overheating can go a long way.