We have four different types of hummingbirds in the Pacific Northwest, and Anna’s is the only one that doesn’t always migrate south to warmer spots for the winter. They used to, but biologists say over the last couple of decades that has changed. Prior to the 1930’s, it nested no farther north than San Francisco. However, a combination of plentiful nectar feeders and urban gardens seem to have lured them to overwinter in the colder climes of our region.
It’s also thought the Anna’s Hummingbirds are able to winter so far north because of their fondness for insects and arachnids. Not only does their buggy diet provide nutrients when flowers stop blooming, but they also provide a slower metabolizing source of food to help them survive long winter nights. However, they do live a precarious existence and rely on our help, especially when the temperatures drop below freezing.
If you provide a feeder for hummingbirds, and have regulars who rely on it, it’s important to ensure the feeder is available during cold spells. You’re not encouraging it to stay, but ensuring it might survive. One way to keep the nectar from freezing is to invest in a heated feeder, otherwise you’ll have to rotate feeders, removing and replacing as necessary. Some people bring their feeders in at night to keep them from freezing, and get up at the hint of daylight to rehang them when they know the tiny birds will be rousing.
The size of Anna’s may also help this hummingbird tolerate the Pacific Northwest winters. They are more stocky than other species and weight a few tenths of a gram more than other hummingbirds. However, the real survival tool is an ability to become hypothermic. This is called torpor, a type of deep sleep and by doing so, the little bird consumes 50 times less energy than when awake. When torpor takes place for long periods of time during winter it’s known as hibernation.
Torpid hummingbirds often appear to be dead. During our last cold spell, my mom saw a little bird hanging upside down from the feeder. However, when she went to investigate the hummingbird flew off, much to her relief. Awakening fully from a night of torpor takes a hummingbird about 20 minutes. Shivering is sufficient to warm a little bird’s body by several degrees each minute, and the bird awakens with enough energy reserves to get his through to his first feeding of the morning. Isn’t nature amazing?
We are keeping close watch on our feeders this week and leaving our Christmas lights on for longer periods to help provide a source of warmth. The photo of this Anna’s was taken during yesterday’s snow storm when temperatures hovered around 29 degrees. The little bird would sit for extended periods on the strand of lights, and then eagerly sip nectar from the nearby feeder. We suspect he was loading up for a long night hunkered down in the evergreens next to our house. This morning, a feeder with room temperature nectar awaits his return, as do we.