In most of the dragonfly swarm reports I’ve been getting, I’ve had people tell me that they know nothing about dragonflies or how to identify them, though several of you have an expressed an interest in doing so. So, I thought I would do something to help all of my ambitious reporters out! Today, I’m posting images and descriptions of the most common of the American migratory dragonfly species, including males and females when they’re different, so that you can try to identify some of the dragonflies you’re seeing in those swarms. The migratory species are all dragonflies, not damselflies (see my past post on the subject if you aren’t sure how to tell them apart!), and fall into two families: the darners (Aeshnidae) and the skimmers (Libellulidae). You’re probably not going to get close enough to these to see some of the wing structures that make it very easy to tell these two families apart (I’ll be posting on this eventually), but the most common migratory species all look different enough that it should be pretty easy to distinguish them on the wing.
Let’s start with the darners. The family Aeshnidae contains the biggest species of dragonflies in the world, so if you’re thinking, “Wow! That’s a REALLY BIG dragonfly!” it likely belongs to this group. The most commonly observed darner is this:
This is the common green darner or Anax junius. This species is the most commonly reported migratory dragonfly in the U.S. and will be seen very often in swarms. Things to look for: 3 inches long. Bright green thorax in all individuals. Bright blue markings on abdomen in mature males, green markings on brown bodies in females and immature males. Some immature males might also have red abdomens. “Eyespot” on top at front of head (clearly visible in image of male – click on the image if you wish to enlarge it). Clear wings or with only minor duskiness, no distinct spots or markings. Green darners are found throughout the United States and in southern Canada.
The other common migratory darner is this one:
This is the swamp darner or Epiaeschna heros. If you live west of central Texas, you’re not seeing this one in your swarms! Anywhere else, this is a darner commonly found in swarms. Things to look for: Very large dragonfly, up to 3.5 inches long. Dark brown body with narrow, bright green stripes on abdomen, thick green strips on sides of thorax. Bright blue eyes. Males and females similar, though female may lose some of the blue as she ages. This dragonfly is found only east of Ohio in the north and east of Nebraska and Texas further south.
That’s it for the common migratory darners! Most of the time, if you’re seeing what you think are very large dragonflies in a swarm, it will be one of the two species above. Most of the Libellulidae (also known as skimmers) are smaller than the darners, though they’re still pretty big. Most of the migratory skimmers are also very common species of dragonflies with wide ranges in the U.S.. These include this gorgeous skimmer:
This is the twelve spot skimmer or Libellula pulchella. This is a very common skimmer found throughout most of the U.S. (except for the southwest) and southernmost Canada. Count the number of black spots on the wings and you’ll know where it got its common name. Things to look for: Medium-large dragonfly, 2 inches. Body dark brown, males often with white prunescence on thorax and abdomen. Females similar, but lack most of the prunescence. Three dark spots on each wings, including one at the base, middle, and tip. White spots may be present between the black spots. The eight spot dragonfly is similar, but the dark spots do not reach the edges of the tips of the wings.
This species is very closely related to the 12 spot:
This species is the painted skimmer or Libellula semifasciata. It’s range is similar to the swamp darner above and is restricted to the eastern half of the U.S. Things to look for: Medium-large dragonfly, just under 2 inches. Pattern on wings is distinct: amber coloration at base and tip, brown spot at center and near tip. Abdomen with a subtle orange-yellow tint in males, tending more toward brown in females. Sexes very similar otherwise.
Now we have some gliders, my favorite dragonflies!
This is my favorite dragonfly, the wandering glider or Pantala flavescens. Considering my long-standing interest in dragonfly responses to weather patterns, there’s a good reason for this dragonfly to be my favorite. But that’s a story for another time. For now, you’ll want to look for these characteristics: Medium-large dragonfly, just shy of 2 inches. Wings long relative to body, broad. Body yellow brown, but can appear golden in flight. Abdomen tapered, thicker at base than at tip. Males and females similar. This species is common across the U.S. and southeastern Canada.
The wandering glider’s close cousin is this species:
The spot-winged glider, or Pantala hymenaea, is very similar in shape to the wandering glider, but bears some distinctive differences. Things to look for: Medium-large dragonfly, just shy of 2 inches. Abdomen grey and black, appearing mottled, and tapering to a point. Wings long and broad, mostly clear with a distinctive dark round spot at the base of the hindwings (look for the spot in the center of the hindwings right next to the body in the image above). The location and shape of the spot spot is only seen in this species. Males and females similar. Found throughout most of the U.S. and southeastern Canada.
And finally, we come to the saddlebags. The first saddlebags is this:
This gorgeous dragonfly is the Carolina saddlebags or Tramea carolina. This group of dragonflies is rather closely related to the gliders, which should be obvious if you compare the shape of the wings. Things to look for: Medium-large dragonfly, 2 inches. Long, broad wings. Hindwings with wide deep red-brown spot at the base. Body bright red, with two black abdominal segments the near tip of the abdomen. Males and females similar. Common across most of the eastern U.S. Note: this species may be replaced by the red saddlebags (Tramea lacerata), which looks nearly identical, in swarms if you are in the western part of the country. The red saddlebags hasn’t ever been officially declared a migratory species, however. You can distinguish the two by looking at the color of the face (Carolina has a violet forehead while red does not) and the black abdominal segments (the black doesn’t wrap all the way around the sides of the segment in the reds as it does in the Carolinas), but these characteristics may be difficult to distinguish in the field. Luckily, the ranges of these species don’t overlap very much except in eastern Texas and Oklahoma.
And finally, we have the other very common saddlebags:
This is the lovely black saddlebags or Tramea lacerata. I think this one is gorgeous! Sleek black dragonfly, very common in Tucson. Love it! Things to look for: Medium-large dragonfly, just over 2 inches. Long, broad wings with broad brown-black spot filling the 1/4 of the hindwing closest to the body. Abdomen black, often with white spots on the upper surface near the base and the tip of the abdomen. White spots darken over time. (You can see the white spots in the image above – just click on the image to enlarge it, and look halfway between the end of the wings and the tip of the abdomen.) Males and females similar. Common throughout much of the U.S. except in North Dakota, Montana, and Wyoming.
That does it for the dragonfly species you’ll commonly find in migratory swarms! I suspect that many of the same species are present in static swarms as well (please see my post Dragonfly Swarms Revisited for more information about the two types of swarms), so hopefully this post will be handy for those of you who wish to ID the dragonflies you’re seeing in swarms. Next time I’ll cover the less common species of migratory dragonflies and comment on some of the other species that have been popping up in swarms around the country. Until next time!
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