By LESLIE BISHOP, guest columnist
Summer is in full swing. On these hot, humid July days, if I am not swimming in the pond, I am watching the constant entertainment at the hummingbird feeders.
The Ruby-throated Hummingbirds seem to intensify their activity as summer progresses. They zip among the blooming hostas and phlox and dive-bomb each other in competition for the feeders. It is a challenge to keep the feeders loaded with sugar water, but lately I have had to refill a couple times a day.
What a surprise to see two Downy Woodpeckers slurping the sugar water at the hummingbird feeders this morning! Even though they are the smallest woodpeckers in Indiana, they look huge next to the tiny hummingbirds who were also at the feeder.
Sturdy, elongated woodpecker beaks with chisel-like tips can drill holes in trees to find insects, whereas the long, slender beaks of hummingbirds can probe elongated flower tubes for nectar.
[sc:text-divider text-divider-title=”Story continues below gallery” ]But these beak adaptations do not mean that the two species are distinctly different in their diet. Ruby-throated Hummingbirds also eat large numbers of insects. They will perch on a tree limb and swoop down to nab a gnat, mosquito or fly. Hummers will also actively forage up and down a tree trunk for crawling insects or spiders.
Likewise, the diet of woodpeckers is not rigid. In the winter, they shift to a seed diet, and in the spring, they will sip sugary sap that oozes from tree bark wounds.
Long beaks alone aren’t enough to reach the sugar water in the tubes of a hummingbird feeder. Both woodpeckers and hummingbirds have unusually long tongues, but each have unique characteristics.
Since the 1800s, biologists have believed that hummingbirds use capillary action to draw in nectar along the grooves in their tongues. But a recent study at the University of Connecticut contradicted that belief and showed that hummingbird tongues act as elastic micropumps — the tongue flattens out as it reaches out and bends in as the groove fills with nectar. This reshaping of the tongue happens rapidly and allows the hummer to drink much faster than would be possible with capillary action.
Woodpecker tongues are equally complicated. Depending on the species, their tongues can be three to four times the length of the bill. After drilling a hole in a tree, a woodpecker uses its long, sticky tongue with backward barbs on the tip to probe and capture insects. The movement of the tongue is controlled by muscles attached to a complex of bones called the hyoid apparatus. All vertebrates have hyoids, but in birds, the hyoid defines the shape of the tongue and its movement. In Downy Woodpeckers, these bones extend from the base of the tongue and fork to continue over the back of the skull, just under the skin, and continue over the top of the skull to the base of the eyes. This apparatus provides a cavity to store the long tongue when it is not in use.
Woodpeckers aren’t the only visitors to hummingbird feeders. In May and June, many people reported numerous Baltimore Orioles at their feeders. In addition, others have reported chickadees, goldfinches and warblers as visitors. Some of these species have tongues that can reach the nectar, and others do not. Some birds may visit out of curiosity to see what the activity is all about, and others may seek insects that are attracted to the sugar water.
My hummingbird feeders are empty again. After I take a dip in the pond, I will load them up. In fact, I think I will join the party and get my tongue busy licking an ice cream cone.
Leslie Bishop is a Brown County resident and retired biology professor from Earlham College. She can be reached through the newspaper at [email protected].
