Dragonflying

“Dragonflying is good for jaded birdwatchers. It presents new challenges,” Cynthia Berger told me as we watched darting dragonflies at Whipple Dam State Park one sunny day in late July. Berger is the author of Dragonflies, an excellent new book designed for beginning dragonfly-watchers.

These “glittering aerial acrobats,” Berger writes in her book, are similar to birds in several ways. Like birds, dragonflies are strong flyers and have distinctive and often colorful bodies. Many defend territory, guard mates, and are excellent aerial predators. The female and male of a species are frequently different in appearance, as different as male and female black-throated blue warblers, rose-breasted grosbeaks, or indigo buntings, and, like those birds, the males are the flashier. Several dragonfly species migrate south in the fall and north in the spring. They also can be watched through binoculars, although close-focusing binoculars, designed for both butterfly- and dragonfly-watching, are better than birdwatching binoculars as I discovered when I used Berger’s on our Whipple Dam outing. Finally, dragonfly-watchers, like butterfly-watchers and birdwatchers, can make original discoveries about species’ distribution and behavior.

Dragonfly-watching has really taken off in this century with the publication of two user-friendly, dragonfly field guides: Sidney Dunkle’s Dragonflies Through Binoculars (2000) and Beginner’s Guide to Dragonflies by Nikula, Sones, Donald and Lillian Stokes (2002).

Dunkle is an odonatist or odonatologist–someone who studies dragonflies–and earlier wrote two excellent guides to the dragonflies and damselflies of Florida. Back in 1978, Dunkle, along with Dennis R. Paulson and under the auspices of the Dragonfly Society of the Americas, dreamed up most of the common English names for all 425 North American dragonflies and damselflies. This made dragonfly-watching more accessible to nonscientists. Many names are site specific such as swamp darner, Ozark clubtail, and Pacific spiketail. Others refer to the dragonfly’s color–roseate skimmer, azure darner, coppery emerald, cinnamon shadowdragon. Then there is my own personal favorite, the species that sent me to the books, the comet darner.

Living on a dry mountaintop, as I do, I wondered why I often saw dragonflies coursing above the grasses of our First and Far fields. With the help of Dunkle’s guide, I identified common green darners, twelve-spotted skimmers, and common whitetails. All are large, showy species easy to see even through my birdwatching binoculars.

But back on August 19, 2003, I was dazzled by a new species. As I walked across First Field toward Big Tree Trail, dozens of huge, flashy dragonflies, which I later identified as comet darners (Anax longipes), zipped around me like miniature helicopters on speed.

“Heavenly Day,” lepidopterist Alexander B. Klots said when he first saw a male comet darner, “isn’t he a beautiful thing on the wing! With that emerald green of the thorax and blood red of the abdomen…” The male comet darner also has a greenish-yellow head and unusually long legs, hence the longipes species name that means “long legs.” Virginia Carpenter, author of Dragonflies and Damselflies of Cape Cod, published back in 1991, calls the comet darner “easily our most spectacular dragonfly…a fleet, powerful insect which flies with an easy, fluid grace…bird-like [in]size…and..rarely seen at rest.”

For more than three weeks, male comet darners hawked insects over First Field, and never once did one land while I was watching. Carpenter claims they are so swift that they are hard to catch. And they are fierce predators. She saw one with three dragonflies, half the size of its 3.2 inches, in its grasp. Dunkle wrote that the comet darner’s preferred habitat is borrow pits or semipermanent, usually shallow, grassy ponds without fish. We don’t have those close by, but apparently dragonflies do gather in swarms to feed on abundant prey miles from where you might expect to see them, which explains why I see so many above our fields. Members of a feeding swarm ignore each other and often consist only of males.

While the comet darner swarm only appeared here in 2003, the common green darners (Anax junius) are attracted to First Field every year in late summer. I sit on Alan’s Bench and watch them zip about for hours. Only slightly smaller than comet darners, common green darners have bright green thoraxes and azure blue abdomens adorned with a vertical dark brown stripe. The most widely distributed darner of its genus, it can be found in all 50 states, as well as in Canada, Mexico, the Caribbean, and even Asia. They also like to breed in temporary, fish-less ponds.

Some common green darners migrate; others are residents that remain in ponds as nymphs throughout the winter. Of the 300 dragonfly species in North American, only 16 species from two families–the darners and skimmers–migrate. Usually they fly in air currents high above humans’ sight. Many migrate singly, but sometimes huge swarms migrate. In 1992, more than a million common green darners were counted along Lake Michigan’s shore at Chicago, Berger says. Like birds they follow land forms and seem to know their way instinctively.

Often, hawk watchers report seeing dragonflies too. Late last August, Rudy Keller was counting hawks at Hawk Mountain Sanctuary, and he reported on the Pennsylvania butterfly and dragonfly listserv that “dragonflies were constantly moving by North Lookout or passing through binocular fields during my scans for raptors. Local redtails, passing kestrels, and even sharpies were stooping on, capturing and eating them as snacks on the wing all afternoon…” Keller was able to identify black saddlebags and twelve-spotted skimmers, both of which migrate. Merlins also prey on migrating dragonflies. Other bird species that relish dragonflies of all kinds are common nighthawks, swifts, swallows, flycatchers, and purple martins, all birds that catch their prey on the wing, using their mouths as dragonflies do when “hawking” food.

Dragonflies can fly for hours nonstop, averaging 25 to 35 miles an hour when they are migrating, and they travel thousands of miles. “Dragonflies,” Berger writes, “can take off backward, launch vertically like a helicopter, hover motionless for more than a minute, execute an unbanked turn, make a series of dazzling zigzag maneuvers, and stop on a dime.”

They also have eyes that wrap around their heads so they can see in almost every direction at the same time. Their color vision is better than ours–they can see four or five to our three primary colors, including ultraviolet light. Because of their superior eyesight, they only use their eyes to find prey. They eat flying insects including other dragonflies and need at least ten to fifteen percent of their body weight in food every day.

The insect order to which both dragonflies and damselflies belong–Odonata–means “toothed ones,” which refers to their sharply serrated lower jaw that they use to grab their prey. While dragonflies are big and stocky with wings that spread out flat when they are perched, damselflies are little and dainty and fold their wings over their backs when they are perched. The ebony jewelwings or black-winged damselflies (Calopteryx maculata) sit on vegetation overhanging our stream bed looking, as Virginia Carpenter observed, “like so many little black bows tied gaily to the tips of branches.”

During my time at Whipple Dam State Park with Cynthia Berger, we saw three species of damselflies–familiar bluets along the side of the lake, eastern forktails, which Berger says are monogamous, over the water, and ebony jewelwings at the edge of the outlet stream in the shaded forest.

“I always think they’re fun to see,” Berger commented as a couple chased back and forth. Both were males because of their black wings and striking, dark, metallic green bodies. Females have a white stigma (a blood-filled blister at the tip of each wing) on each brownish wing and dull, bronze-colored bodies.

Male ebony jewelwings defend territory for as long as a week from ten in the morning until four in the afternoon and mate with numerous females over that time period. After a fluttering courtship display, a male ebony jewelwing grabs a female at the top edge of her thorax with four claspers from the tip of his abdomen. Then they fly in tandem, the male leading and dragging the female along until they can form what is called a “copulation wheel.” She grasps the tip of his abdomen with her legs and folds her abdomen up under her thorax, pushing the tip of her abdomen against his genitalia. Dragonflies do this while flying; damselflies while on secluded perches.

To my delight, Berger and I spotted a pair mating on the leaves of a hickory sapling beside the stream. The “wheel,” though, looked more like a Valentine heart. We also saw another male open his wings and then clap them shut. Berger says that both sexes may do “wing-clapping” to signal their location, to cool their bodies on a warm day, or to improve the intake of oxygen.

We didn’t stay to watch the female lay her eggs on floating or submerged water plants while the male guarded her and tried to court other females at the same time. I was content to have seen the three damselfly species and three dragonfly species–twelve-spotted skimmers, common whitetails, and widow skimmers. But Berger was disappointed.

“Oh, it was so much better the last time I was here,” she told me.

Spoken like a true birdwatcher!

Cynthia Berger’s Dragonflies is published by Stackpole Books and not only covers the life history of dragonflies and damselflies, but tells readers how they can attract them to their backyards. The book is beautifully illustrated in color and includes paintings and species accounts of the most common dragonflies and damselflies. Its comprehensive Resource section should help anybody interested in becoming a dragonfly-watcher.