Ruby-throated Hummingbird at a Feeder  (Terry W. Johnson)

By Terry W. Johnson

Throughout spring and summer, we Georgians spend a lot of time watching ruby-throated hummingbirds feeding at our hummingbird feeders and flowers. These visitations are so frequent one might think that the food we provide them is all these birds need to survive. However, the truth is hummingbirds require far more than the sugar provided by sugar-water solutions and the nectar of flowers to prosper.

The belief that hummingbirds can survive solely on nectar alone is not new. In fact, it was once so widespread that when zoos and other facilities first tried to display hummingbirds in captivity the birds were fed nothing but sugar water. When all of these efforts failed, it became clear hummingbirds require a more varied diet. After much experimentation, these early aviculturists learned that the birds also needed protein.

In an effort to determine the source of this protein, biologists analyzed the stomach contents of many hummingbirds. This led to the discovery that hummingbirds eat a wide range of invertebrates, such as tiny spiders, mosquitoes, aphids, flies, gnats, beetles, leafhoppers and caterpillars. Some stomachs examined contained dozens of these tiny animals. Yet, because the researchers could not detect any nectar, some suggested that hummingbirds actually visit flowers hunting insects rather than nectar.

Today, such theories do indeed seem weird. But remember that early scientists didn't have technology needed to detect nectar. Nor did they know that nectar is digested very quickly. Nowadays, it is common knowledge that a complete hummingbird diet consists of nectar (manmade and natural), invertebrates and a number of other food items.

One such food is tree sap. In winter, the most common source of sap in Georgia is sapsucker holes. These sap wells are excavated by a woodpecker known as the yellow-bellied sapsucker. This odd woodpecker – a winter resident here – chisels through the outer bark of a variety of trees to create the tiny reservoirs. The sap that wells up in these excavations is the bird’s primary source of food. But other animals also eat the sugary liquid, including squirrels, butterflies, Carolina chickadees and hummingbirds.
After the sapsuckers leave the state at the end of winter, hummers often find sap in broken tree limbs that exude it.

Hummingbirds are also fond of fruit juice. While the rubythroat's bill may appear sharp, it is blunt and incapable of piercing a peach, apple, pear, fig or other fruit. However, they will eat juice from fruit that has been partially eaten or punctured by a bird or other animal. My wife and daughter once had the rare opportunity of watching a ruby-throated hummingbird feeding on a fig. The bird dined by dipping its bill into a hole pierced in the ripe fig by another bird.

To me, one of the most fascinating revelations concerning the diet of the ruby-throated hummingbird is that invertebrates may be a far more important component to their diet than we previously realized. Dr. Doug Tallamy, professor and chair of the University of Delaware’s Department of Entomology and noted proponent of incorporating native plants in residential landscapes, puts it this way: “Hummingbirds like and need nectar but 80 percent of their diet is insects and spiders. … If you don’t have those insects and spiders in your yard, it doesn’t matter how many hummingbird feeders you have, you are not going to be able to support hummingbirds.”

Invertebrates provide rubythroats with the fats and minerals not supplied by nectar, sap and fruit juices. It has long been recognized that female hummers consume large numbers of these small critters while they are feeding their young. At that time of the year, females may eat as many as 2,000 insects a day. They, in turn, feed their young the protein-rich food needed for proper growth and development.

We now also know that adult hummingbirds consume scores of insects and other invertebrates each day. The consumption of these tiny, protein-rich animals only increases during migration.

In a study by the Cornell University’s Laboratory of Ornithology, researchers tracked the movements of a female hummingbird for two weeks. During this time, the bird ate nothing but insects. These revelations have prompted some hummingbirds experts to suggest that perhaps hummers are best described as being insectivorous birds that eat nectar instead of nectavors that dine on insects.

If that’s the case, to attract hummingbirds to our yards, we must emphasize providing these tiny flying jewels an abundant supply of nectar served in feeders as well as plants that not only offer nectar but also attract the insects that play a key role in their diet. Here are a few of the ways you can do that.

• Increase the number of native trees, shrubs and broadleaf plants in our yards. Native plants attract far more insects than introduced species.
• Set aside patches of native plants. Such patches are havens for native insects.
• Add a tree that is used by yellow-bellied sapsuckers to your landscape. (For more on these birds, read Terry’s February 2023 column.)
• Place rotting fruit on the surface of your compost pile or in a small dish to attract fruit flies and other small insects.
• Don’t use herbicides and pesticides on nectar plants, to ensure the nectar is not contaminated with poisons and tiny insects are not killed.

It is obvious there is far more to hummingbird gardening than meets the eye. However, I am one hummingbird fancier who is excited over this new challenge. I know that when I better address the dietary needs of the ruby-throated hummingbird, I will also be creating a more beautiful landscape that will benefit many of other native plants and animals.

Terry W. Johnson is a retired 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.”