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Nature Notes: Hummingbird Moth

Ed Robinson
September 1, 2017

If there is one constant about the natural world around us, it is the opportunity to learn something new every day. No matter how long you have been a keen observer and participant in the outdoors, there is always a revelation just waiting to smack you in the forehead.

It was my good luck to spend two weeks in late July and early August working hours each day in the woods and field around our NY cabin. That’s the time of year when I cut trees for forest openings, split and deliver firewood and spend lots of time caring for the thousands of trees and shrubs we have planted in the last decade. It is a favorite time to be afield because the 45-acre field is alive with flowering plants, and you can observe large numbers of pollinator species gathering pollen and nectar.

On a perfect summer afternoon, I spent a couple of hours with my camera trying to capture quality photos of various pollinators at work. With thousands of butterflies, bees, flies, beetles and moths flitting back and forth, my biggest problem was getting my photo subjects to pose for more than a split second. Thanks to the magic of digital cameras, I kept clicking away knowing I could screen all my shots for a few winners.

Later, sitting on the deck with a cup of tea, I reviewed several dozen photos. In the middle of the pack I noticed an unusual hummingbird feeding on a lavender thistle blossom. The body shape and blurred wings looked right, but the coloration was unlike any hummingbird I had ever seen, and the head really confused me. Perplexed and eager to understand what I had captured, I went to work with a computer. It was soon evident that I had observed not a hummingbird, but my first hummingbird look alike or mimic.

Specifically it was a hummingbird clearwing moth, Hemaris thysbe. As you can see from the photo, this creature is a riot of color with a rounded body shape that makes you think you are watching a bird, not a large and extravagant moth. The clearwing and other members of the Sphinx (Sphingidae) family are large moths (1.5–3 inches long) with sizable wings capable of rapid wing beats, making them strong fliers. The wingspan may reach five inches or more, and the hairs on the tail open to resemble a fan, probably to help in maneuvering. If you watch them in flight, as I was able to do on two more occasions, you can understand the confusion with hummingbirds because these moths are capable of the same rapid starts and stops, and the precise hovering over a targeted flower. They have been documented in many parts of the US, as well as in southern Canada and Mexico.

The name “clearwing” results from the construction of their wings. Unlike birds, moths do not have feathers but a series of tiny scales on their wings. Where the scales are not present, the wings end up looking transparent or clear. A noticeable feature of the moths are the large antennae on their heads, absent on hummingbirds. Another difference from the hummingbird is the manner in which these moths access plant nectar. Instead of a rigid beak and hollow tongue, the moths use a long, flexible proboscis that rolls up when not in use.

While most moths are more active at night or in low light conditions, the hummingbird moths favor daylight hours, although they may also feed at night. Not surprisingly, the moths are most often spotted between June and August when flowers are in bloom. The female moth attracts her mate using pheromones. She then lays her eggs one at a time on favorite host plants, or on fallen leaves. The caterpillar that results is a greenish yellow, with dark green lines and red spots. The caterpillars are a desirable food item for birds due to their fat and protein levels.

A common name for this family of moths is “hornworms,” in reference to the caterpillar or larval stage. Each caterpillar has a hook shaped protrusion on the posterior end – don’t worry, the hooks are harmless. While the larvae like to feed on honeysuckle, hawthorn, cherries and plums, the caterpillars can be destructive when they target crops such as potatoes or ornamental plants.

Other reported members of the hummingbird moth family are the Nessus sphinx, snowberry clearwing and white-lined sphinx. Their color patterns vary widely, from dark burgundy to golden olive, yellow or white. One website I referenced, dealing with all the butterflies and moths of North America (Lepidoptera), noted that sightings of some of these moths are unusual, and asks people to report them with photographs if possible. Scientists are still trying to understand the distribution and lives of these fascinating creatures. It is known that the moths favor phlox, bee balm, dogbane verbena and butterfly bush. Having an abundance of these favored plants for pollinators on your land is obviously one way to increase the odds of seeing one of these moths, but an over-population of the moths, and their caterpillars, would be of concern to gardeners and farmers.

My friend Tulle Frazer reports that she has seen a hummingbird moth in her Harpswell garden. If other readers have seen them, I would enjoy hearing from you. Thanks! I can be reached at erobin77@gmail.com.

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