By Terry W. Johnson
As far as many Georgia hummingbird fanciers are concerned, 2020 has been a disappointment. It seems that throughout the spring and early summer they have seen far fewer ruby-throated hummingbirds in their backyards than expected. The apparent lack of these popular flying jewels has spawned concern that the population of ruby-throats has plummeted in much the same way monarch butterflies have.
Did the tiny birds meet an untimely end migrating to or from their wintering grounds? Some have suggested that weather or perhaps a lack of food led to widespread mortality during the winter. Others wonder if our warm, wet spring resulted in the birds migrating through Georgia quicker than normal.
Since I am not aware that biologists have detected a precipitous decline in ruby-throats, with the arrival of July we should soon learn whether ruby-throats are in trouble or not. The reason why: July is the month when hummingbirds begin preparing for, and in some cases actually beginning, their fall migration. And, significantly fewer ruby-throated hummingbirds passing through our backyards this summer would suggest a precipitous decline in this popular bird.
Preparation for this awesome migration event actually begins shortly after June 21. This date is far more important to wildlife than for humans. June 21 is the longest day of the year. Throughout the rest of the summer, with each passing day the amount of time Georgia is bathed in sunlight diminishes. The declining daylight triggers chemical changes in the bodies of hummingbirds and other migratory birds.
In the case of ruby-throats, they develop a seemingly insatiable hunger, which leads to a feeding binge. During this time a ruby-throat consumes more food than it requires to fuel its normal day-to-day activities. This allows the hummingbird to store the energy as fat—fat that represents the fuel needed to reach its winter home.
As such, from now into September a hummingbird that weighed about 3 grams in June will tip the scales at anywhere from 4 to 5 or more grams before it embarks on its fall migration to wintering grounds that extend from southern Mexico southward into Central America.
Much of this food is gleaned from nectar-rich flowers. In fact, it would not be unusual for a hummingbird to visit 1,500 or more flowers in search of nectar. In this quest, hummingbirds also begin frequenting our backyards more often. In suburban and urban areas where hummingbird fans roll out the welcome mat by providing the birds with an abundance of nectar plants and feeders, hummingbirds are able to consume huge amounts of food in less time than they can elsewhere. Having to use less energy to obtain the needed food enables them add fat without expending a large amount of effort.
The ruby-throats we will see in our backyards this summer are a combination males and females that bred locally and their offspring, as well as migrants en route to points south. In fact, in summer before migration begins, the hummingbird population in Georgia is larger than at any other time of the year.
With that in mind, as the numbers of hummingbirds visiting our backyards swell, we should soon know whether there are fewer hummingbirds preparing to migrate south than was the case a year ago.
If you want an idea how many hummingbirds you are feeding during the next few months, count the most you see at one time during the day and multiply this number by six. That will be approximately the total number of hummers you are feeding throughout the day. In other words, if you count six birds, you are actually hosting 36 hummers. Keep in mind, this technique only works during summer.
Some Georgians will host 100 or more hummers in July and August. Most of us, though, will see far fewer. (It has been my experience that the people who consistently have the most hummers provide the birds with a combination of nectar plants and feeders.)
If for some reason we see far fewer hummers than we normally do, we will know the ruby-throated hummingbird population is waning. However, I will be shocked if this proves to be the case.
Terry W. Johnson is a former Nongame program manager with the Wildlife Resources Division and executive director of The Environmental Resources Network, or TERN, friends group of the division’s Nongame Conservation Section. (Permission is required to reprint this column.) Learn more about TERN, see previous “Out My Backdoor” columns, read Terry’s Backyard Wildlife Connection blog and check out his latest book, “A Journey of Discovery: Monroe County Outdoors.”