As the days have gotten shorter and colder, I have wondered whether or not it is time to remove our hummingbird feeder. Timing-wise, I know that some hummingbirds start migrating in mid-July and others wait until August or September. But I wonder if these tiny, energetic birds have all left for the winter or if there may be a few stragglers still hanging around.
It turns out that most hummingbirds do, in fact, migrate. There is even a species of hummingbird (the rufous) that makes the longest migration for its size of any bird on earth, traveling from Alaska to Mexico! Most head for sunny climes in the Caribbean, Central America, Mexico, and even South America. However, there are some that are not. And if they don’t, they definitely need a place to stop and feed.
Hummingbirds have the highest metabolism of any endothermic animal on earth. Endothermic refers to the fact that hummingbirds, like humans, must generate their own body heat to stay warm. Whereas a high metabolism means they require a large amount of calories to sustain themselves and live to fly another day. In addition to feeding on tree sap and nectar for calories, hummingbirds are carnivorous, feeding on insects and spiders that cannot normally survive winter temperatures. The sugar water we provide them and the flower nectar they feed on is simply fuel for their insect and spider hunting activities. Needless to say, flowers that produce life-giving nectar are also not usually available in cooler temperatures.
But the times are changing! And our environment is changing too! Climate change has given way to an alteration of ecosystems. Milder temperatures in some areas allow flowers to bloom year-round and insects to breed year-round as well. Hummingbird feeders are also left out longer and year-round, which contributes to the hummingbirds’ food supply and ability to sustain themselves.
Finally, hummingbirds use torpor to survive, since they cannot see or feed at night. Similar to hibernation, torpor allows hummingbirds to slow their heart rate, conserve energy, and even lower their body temperature to match the surrounding air. It is said that hummingbirds can save between sixty-five and ninety-two percent of their energy during torpor and that their heart rate can plummet from just over twelve hundred beats per minute to a whopping fifty beats per minute. minute. However, even using torpor, hummingbirds can lose around ten percent of their body weight overnight, but it is still an invaluable tool for their survival.
Hummingbirds are fascinating creatures and much remains to be learned about their migration patterns. I hope this glimpse of their great ability to survive even in harsh conditions fuels your interest in learning more about these wonderful little wonders!