We’ve reached that perfect point in the summer when you can’t walk ten feet through the park without a dragonfly swirling over your head. Since dragonflies are one of my very favorite things on earth, I thought I’d give a little blog spotlight to the ones I’ve seen in Overton Park over the last few weeks. There are more than 300 species of dragonflies in the United States alone (almost 3,000 worldwide), and about 10 of those are commonly seen in our park.
This time of year, it’s not uncommon to see large swarms of dragonflies flying together. These are called static swarms, and their purpose is generally the same as a buffet: all eating, all the time. This is why the swarms are especially noticeable after the Greensward has been mowed: the process of cutting the lawn stirs up all the little insects that dragonflies like to eat, so they come together for a feast.
Feeding swarms are usually made up of several species of dragonflies that can be classified as “fliers.” (As opposed to perchers, fliers are pretty hard to find sitting down, which makes photographing them a challenge.) The vast majority of the fliers in our park are two species: the wandering glider (here seen in a rare perched moment)…
…and the spot-winged glider (successfully netted, admired, and released).
Both of these dragonflies are yellow, although the wandering glider tends to be brighter than the spot-winged. They can fly for hours at a time, even across oceans; this is why the wandering glider is the only dragonfly species that can be found almost all over the world. It can fly just about anywhere!
Another flying species is the black saddlebags. It’s named for the large black spots on its wings.
While Rainbow Lake isn’t an ideal ecosystem (since it’s shallow, made of concrete, and has no naturally-occurring vegetation), many dragonflies live near water. Thus, you can find several skimmer dragonflies hovering and perching around the lake, including the slaty skimmer. They’re large, dark-purplish-to-black, and they often perch high in vegetation after patrolling over water.
One of our most common dragonflies is the blue dasher. This is a fairly small dragonfly, with males showing a blue abdomen and females more yellow-ish, but both having a tiger-striped thorax. They’re also pretty friendly–blue dashers will sometimes land on people, or at the very least not fly away when approached. In this shot, the female is on the left and male on the right.
The eastern pondhawk is slightly larger than the blue dasher. Males can sometimes be confused for each other, but eastern pondhawks always have a green face, while blue dashers’ faces are white. Males are blue and females are green, and they like to perch on the ground.
Eastern amberwings are the smallest of our dragonflies in this area. They’re very easy to confuse for wasps unless you get up close, but they’re much more likely to be hovering over the edge of a pond than a wasp is. Males have bright amber-colored wings; females are less showy but have more intricate markings. In the below photo, the male is on the left and female on the right. I tend to see females in the grass and males by the pond, except of course when they come together to mate and lay eggs.
Finally, the widow skimmer is a dragonfly that sometimes joins the large feeding swarms, but often stops to perch in the grass or on plants rather than flying continuously. They’re named for the bands of brown-to-black markings on their wings. Males have an extra band of white coloring outside the black lines. Their graceful flight is very much like a butterfly’s.
I hope you’ve enjoyed this small peek into the world of dragonflies! The static swarms should last another couple of weeks or so, and then you’ll see sparse amounts of dragonflies through about mid-October. After that they’ll disappear again until about April, so enjoy them while you can.
August 2017 update: Want to see all the dragonflies we’ve recorded in Overton Park? Head over to our place page on iNaturalist and check out the insect section!