Volunteers monitor DuPage's dragonfly population

When you spot a dragonfly, your mind may flash on the many myths surrounding these intriguing creatures.

Or you may shy away, intimidated by the insect's sleek, sharply pointed and deceptively threatening appearance.

If you're a DuPage County Forest Preserve District volunteer dragonfly monitor, you'll simply count.

It's that time of year, when migrant dragonflies return to the area and larvae overwintering in the depths of local waterways emerge. It's time for the dragonfly census.

The district is looking for volunteers ages 18 or older to conduct regular surveys at designated forest preserve properties so the relative health of local dragonfly populations, and the health of their close relative, the damselfly, can be assessed.

“We like for beginners to focus on 10 to 20 species they would more commonly see,” said Cindy Hedges, the district's stewardship program coordinator. “We don't expect people to come in and be experts right away.”

A workshop aimed at introducing the volunteer dragonfly monitor program to potential volunteers is set for 6 to 8 p.m. Tuesday, March 15, at the district's Grounds and Resources Complex, 29W220 Mack Road, West Chicago.

“This is something people can come to, to see if it's something they're interested in,” Hedges said. “It's geared to anybody interested in conducting surveys.”

Dragonfly status gives biologists clues to the health of the overall environment.

“They are a very useful indicator species,” said Andres Ortega, an invertebrate ecologist with the district's Office of Natural Resources. “The presence or absence of dragonflies can indicate the health of waterways.”

Fewer dragonfly species will be found in polluted waters. Waters fouled by pollutants also support less unique species, which are more susceptible to damage posed by pollution, Ortega said.

“There are 10 to 12 fairly common species across most of northern Illinois and the Midwest,” he said. All told, there are thousands of known dragonfly species on the planet.

DuPage County is also home to damselflies, which are closely related to dragonflies and are in the same scientific order, but are classified in a different suborder, he said. Damselflies are smaller and more fragile, while dragonflies are more robust and are stronger fliers, he said.

Both types of insects are strictly carnivorous, with a diet that consists mainly of other insects, including mosquitoes, midges, beetles and butterflies. They are both predator and prey; Ortega said birds eat dragonflies as do a few mammals, such as raccoons.

Many migrate to warmer climes for the winter and return in early spring. But some spend the winter in DuPage, submerged in the depths of waterways where they remain in the larval stage, he said, until they emerge in spring.

“The larvae will go down deep,” he said. Some larvae, he said, take up to five years to reach maturity, such as the Hines Emerald dragonfly. A small population of this rare species can be found at Waterfall Glen in Darien.

Dragonflies typically make their presence known to people visiting their area habitats.

“They are very easy to spot because they are one of the largest insects we have in the area,” Ortega said. “Dragonflies are a very recognizable type of insect and, in many ways, charismatic, too. They're colorful, strong fliers and strong predators.”

It's also relatively easy to differentiate the different species, he said, because they have distinct wing and body markings. Some even have unmistakably bright blue or green eyes, he said.

Both dragonflies and damselflies breed in water and can usually be found near ponds, lakes and streams, he said.

“They're not very timid. They will actually come very close to you,” Ortega said, adding that dragonfly monitors need not be concerned. “They are not aggressive toward people. They have no stingers. They present no risk to people.”

Ortega said past surveys have indicated that local dragonfly populations have remained steady.

“It hasn't changed that much in recent years,” he said.

Hedges said people who come to Tuesday's workshop will learn about dragonflies and the requirement for serving as a volunteer monitor.

Volunteers are asked to commit to conducting six surveys for a minimum of two breeding seasons.

“People are given a route and an assignment in a preserve,” Hedges said. “A lot of times they have to walk off-trail through different vegetation.”

Each survey takes one to two hours to complete, she said. They are done from May through September on days when temperatures are moderate and the weather is favorable. And they are carried out between the hours of 10 a.m. and 3:30 p.m.

Volunteers record their observations on field data sheets, which are later incorporated into statistical reports, she said.

“Last year we had about 21 volunteers in the program,” Hedges said. “We try to place volunteers in a preserve that's close to home. (But) we have some areas that are a higher priority for us to find out about.”

If you go

What: Dragonfly Monitoring Program Workshop

Who: DuPage County Forest Preserve District

When: 6 to 8 p.m. Tuesday, March 15

Where: Grounds and Resources Complex, 29W220 Mack Road, West Chicago

Registration: Call Cindy Hedges at (630) 876-5929

Cost: Free

Info: www.dupageforest.org