The transition between summer and fall is, for me, a bittersweet time of year. The summer flowers are fading, leaving only seed heads and dried stalks. The tomatoes and cucumbers are struggling, but, on the bright side, my hummingbird feeders are busier than ever, as my tiny visitors prepare to begin their 500 plus mile journey to Central America, where they will spend the winter months.
Missouri hummingbirds spend most of August and a good chunk of September getting ready for their annual migration. In order to fuel their flight, hummingbirds increase their weight by 25 to 50%. While putting on weight to perform more efficiently seems counterproductive to us, the additional weight they gain actually provides the energizing fat they need to be able fly long distances. During flight, a hummingbird’s heart beats at a rate of 1,260 times a minute – 21 times a second – and its wings flap 80 times per second.
Ironically though, preparation for migration takes place at a time when many nectar producing flowers and shrubs as well as insect populations are beginning to decline, leaving the birds with fewer natural food sources. It’s essential then, that feeders are kept full of fresh, clean nectar throughout the fall -- in fact until Thanksgiving -- to help keep migrating birds alive. Feeders left out in November may be visited by hungry species traveling through the area.
Leaving hummingbird feeders up past early September will not keep the birds in the area too long nor will it cause birds to die from cold fall temperatures. Migration is not in any way tied to hummingbird feeders. Migration is triggered by instinctual, environmental factors. Researchers say that shortening daylight hours, cooler temperatures, decreasing food sources and their internal biological calendar are the prime motivations for migration.
Unlike other migrating birds, hummingbirds travel alone, taking the same route each trip. They fly low, close to the treetops so that they can find familiar feeding grounds. Researchers believe that migrating birds consciously seek out the places they found food in the past, anticipating that it will be available for them again. Hummingbirds fly as many as 23 miles in a single day, stopping often for food. They tend to feed heavily in the early mornings, fueling up for a long daytime flight. The midday hours are their prime flying hours, and the late afternoon and evening hours are once again heavy feeding times. Hummingbirds must eat voraciously to maintain their flying weight throughout their trips.
Sometimes heavy rain, unexpected snow or extended freezing temperatures can put a temporary halt to migration. Hummingbirds will try to find a “safe” area for a week or two while they wait for flying conditions to improve. If they happen to get caught in an area during an unexpected cold snap, the birds will take refuge in the most sheltered space they can find. Usually, they look for small crevices or thick vegetation in the downwind side of a tree trunk. In worst cases, they can enter into a state known as torpor. While in torpor, a hummingbird lowers its temperature, slows its breathing and heart rate and ceases any non-essential activity, living off of its accumulated fat. Once conditions improve, the bird will resume its normal feeding and migration patterns. Birds in torpor should be left alone; attempts to rescue it will most likely kill it.
World-wide, there are 366 recognized species of hummingbirds today, 17 of which routinely nest in the continental United States. According to The American Bird Conservancy, six of the 17 species from the U.S. are experiencing decreasing populations and are likely to become threatened or endangered within the next few years. Like so much of our natural world, hummingbirds are beginning to suffer from the results of human activity. Habitat destruction and loss, exposure to toxins, air and water pollution as well as the subtle impacts of climate change are contributing to the decline in numbers.
Although the problems seem insurmountable, individual actions can help slow and perhaps even prevent the declines we are seeing in our hummingbird species. Plant a wide variety of hummingbird friendly flowers that will offer nectar not just in the spring and summer, but also well into the fall months. Including some deciduous and evergreen native shrubs in the landscape gives hummers shelter from inclement weather. Avoid spraying broad spectrum pesticides that kill off all insects, including those beneficial ones. Hummingbirds can eat thousands of insects a day, especially when other food sources are not available. Reduce the number of lawn treatments. Excessive chemical applications to lawns can pollute the water supplies on which the birds depend. Make sure that feeders are frequently cleaned and filled with fresh nectar. Many hummers die each year from diseases caused by dirty feeders.
I hate to imagine a world without these entertaining creatures clustering around my feeders. Let’s work together to keep our tiny visitors well fed and protected so they can continue to bring their delightful bird chaos to our yards. Keep the flowers blooming, the feeders up and the fresh nectar coming. The birds will love you for it.
