Discovering Hummingbird Moths
Holly Berger, Anoka County Extension Master Gardener
As a child, I was completely mesmerized the first time I saw a hummingbird moth. I thought I had discovered a mythical creature or a new species! It turns out that many people are unaware of the existence of hummingbird moths and mistake them for true hummingbirds. We should get to know these unique members of the Sphingidae (sphinx moth) family; these hard-working pollinators add whimsy and beauty to our gardens.
Hummingbird moths are widespread throughout North America, with the clearwing (Hemaris thysbe) and the snowberry clearwing (Hemaris diffinis) being the most common. While they are important to our ecosystem, they are often undetected or misidentified. Their wings beat in a blur and emit a familiar hum, and they move and hover just like hummingbirds do. Upon closer inspection, it is their antennae, straw-like proboscis, mostly transparent wings, and six legs that give them away as insects. They are also slightly smaller than hummingbirds and have a furry-looking body and tail.
While many moths are nocturnal, hummingbird moths are diurnal and feed mostly during daylight. From May to August, they devour the nectar of the same fragrant flowers enjoyed by bees, butterflies and hummingbirds. Their proboscis can reach long-necked blossoms, making them superb pollinators.
With Minnesota’s short growing season, typically only one generation of hummingbird moth is born each year. Hummingbird moths lay their green eggs on the underside of the leaves of host plants such as honeysuckle, hawthorn, cherry, plum, and viburnum. When the larvae hatch and feed, they become chunky, yellowish-green hornworms which are generally harmless to our plants (unlike tomato and tobacco hornworms). Forming brown cocoons, the hornworms overwinter in the leaf litter that many of us remove in the fall. The adults emerge the following spring and live from three weeks to seven months.
Spotting a hummingbird moth was extremely rare for me until a few years ago when I added a pollinator sun garden. Native flowering plants such as monarda, Joe Pye weed, and cardinal flower brought a happy influx of bees and hummingbirds to my yard. Suddenly, I was getting daily visits from hummingbird clearwing moths, too! I am captivated by how enthusiastically and predictably they return all summer. I enjoy watching and photographing my fast-flying visitors, and they seem surprisingly unbothered by my close proximity.
To welcome and protect hummingbird moths, there are some simple but important things we can do:
Grow a variety of plants (especially natives) with fragrant flowers and varying bloom times.
Add host plants and trees for hummingbird moth larvae.
Learn to identify hornworm species, realizing that most cause insignificant damage.
Leave fallen leaves in your garden for moth overwintering and avoid early-spring cleanups.
Avoid using harmful pesticides, including on your lawn.
Embrace a less-than-perfect garden that favors pollinators.
Hummingbird moths still fascinate me; I look forward to their return every spring. I hope future generations can experience the enchantment that these beneficial pollinators bring to our gardens! For more information about hummingbird moths, visit: https://www.fs.usda.gov/wildflowers/pollinators/pollinator-of-the-month/hummingbird_moth.shtml