Hummingbirds are hypothermic. They stop moving, their body temperatures will drop dangerously low and they sometimes pass out when the days and nights get as cold as they have recently.
These little guys burn up a lot of energy buzzing around the skies and they have huge appetites to replace that lost energy.
During the cold winter months, these tiny flying flowers rely a lot on the nectar in your hummingbird feeder. Your feeder can freeze during a really cold night and hummers obviously can’t drink from a frozen feeder.
Plain water starts to freeze at 32 degrees F., but the hummingbird nectar in your feeder starts to freeze (gets slushy) at about 26 to 27 degrees because of the added sugar (nectar formula is 4 parts water to 1 part sugar). So on freezing nights, bring your feeder inside the house before you go to bed to keep it at room temperature … and put it back outside just before sunrise so it will be ready and waiting (and UNfrozen!) when your hummingbird arrives for breakfast.
If you forget to do this and discover a frozen feeder some morning, replace the frozen nectar with a fresh unfrozen supply ASAP.
They need to eat early to get their tiny hypothermic bodies recharged and heated up so they can face the new day. /gary