This tutorial was first written for a topic on mentoring identifiers in the General category. @tiwane requested I put it here in Tutorials. I’ve edited this very little, but do note that this is very specifically for beginners in observing odonates (dragonflies and damselflies) in New England, USA, in the fall. I provide a link to odonates in New York because the person who wanted to know lives in that state.
I thought I would focus on a few species/genera that are very common August through till frost in the northeastern US and the eastern Canadian provinces. I will caution you that I am not an expert in dragonflies and damselflies, so if someone contradicts what I say, they might well be right!
Let’s start with some basics:
- Adult dragonflies are usually much stockier and bigger than most adult damselflies. Dragonflies tend to hold their wings out straight when perched; damselflies hold theirs together over their backs, usually (but beware the spreadwings!). Dragonflies often fly strongly; damselflies appear to be weak fliers (until you swing a net at them, upon which they disappear into the fourth dimension more often than you can believe).
- Adult odonates, much like birds, often look different as adults vs. young adults (or tenerals, as recently emerged odonates are called). Ditto male vs. female. And just to add to the fun, some adult dragonflies get more powdery blue (“pruinose”) as they age. Thus, it is worth paying attention, not only to color, but to overall size, shape, perching habits, and habitat in order to learn odes.
- Larval dragonflies and damselflies live in water and look very different from adults; we’ll ignore them for now.
- As far as I’m concerned, the best way to learn any species, no matter what taxon, is to look at them closely and often, and to invest in a few to many good field guides or manuals. If you can find and attend a field trip or class, great, but that’s not always possible.
- Looking at odonates: Occasionally, they will sit still enough that you can approach closely and quietly and admire them with your bare eyes. Often, however, the little darlings (which have excellent vision, because they are visual predators as adults) will zoom away as soon as you get close; thus, it really helps to have binoculars, especially close-focusing binos. If you get serious, you may want to start using a big insect net, not because you must collect specimens to dissect their genitalia, but because sometimes you need to see them in hand to ID them to species (including examining their external genitalia, by the way). Both dragonflies and damselflies are quite sturdy and, if caught with finesse, can be handled briefly and let go with no harm done.
- Books: I’m not up-to-date on such matters, but I’d say you might want Dennis Paulson’s Dragonflies and Damselflies of the East (since you live in New York State). If you can find a copy of Ed Lam’s beautiful Damselflies of the Northeast, buy it, but be aware that Ed will be publishing his Dragonflies of North America this fall and you want it. Just pre-order it now; I haven’t seen it but Ed is an incredible artist and naturalist and the book will be gorgeous.
OK, enough introductory blather (but feel free to ask more questions). On to a few species you should know.
Here’s a link to the odonates of the state of New York, listed by prevalence of species observations. I’m giving you this because most of the species you see will be in the first 10 or 15 species listed here.
Blue Dasher, Pachydiplax longipennis. Very, very common, especially around ponds and lakes, but also in open areas well away from bodies of water. Often perches on top of a stem or on a leaf. This lovely species is medium-sized as dragonflies go; learn what Blue Dashers look like and compare other dragons to it as you learn. Females and young males have yellow dashes along the tops of their abdomens (like this). Fully adult males have pruinose abdomens, like this. All ages and sexes have wavy yellow lines on the sides of their thoraxes, like this. There are other useful characters as well, but notice these first.
Common Whitetail, Plathemis lydia. Another very common dragonfly; this one often perches on the ground or rocks, not on top of the stems of forbs. As with Blue Dashers, Common Whitetails vary in color patterns by sex and age. Here are links to a fully adult male, a young adult male, and a female. Note the very obvious wing markings and the very obvious pruinose abdomen of the fully adult male. Caution: females look quite similar to female Twelve-spotted Skimmers, so beware!
Eastern Pondhawk, Erythemis simplicicollis: Very common and given to perching on the ground. Yet another species where the female and young adult male vary in color from the fully adult male. Note the pale terminal appendages at the tip of the abdomen; if I remember correctly, pondhawks are one of the few dragonflies with these pale tips.
Meadowhawks, Sympetrum species: Another percher atop forbs and such, and likely to be one of the last dragonflies flying even past a last frost or two. These are smaller than Common Whitetails and Eastern Pondhawks; they are about the size of Blue Dashers. Fully adult males are bright red and stunning. Young males and females are yellowish. There are several species; don’t worry about them now. The only thing “wrong” with meadowhawks, to my mind, is that they signal that fall is coming (even though they start emerging in July).
Let’s turn to damselflies.
Ebony Jewelwing, Calopteryx maculata: You said you know these, so I’m going to assume you know the beautiful adult males. Females have dusky (usually not jet black, like the males) wings with a white spot near the tip. These dance and flutter near small streams and rivers.
Forktails, Ischnura species: The common species are Eastern Forktail, I. verticalis, and Fragile Forktail, I. posita. Both are tiny. Females can be quite hard to ID to species, so ignore them for now. Note the subtle differences in thoracic stripes between adult male Eastern Forktails and Fragile Forktails.
Bluets, Enallagma species: So many bluets, so little time. I can tell you there are 17 species of Enallagma in Massachusetts; I don’t know how many there are in New York. In general, they are the beautiful blue-and-black damselflies so common around most waterbodies, but beware blue-form female forktails. And should I even mention Scarlet Bluets and Orange Bluets and Vesper Bluets? I certainly shouldn’t tell you about Rainbow Bluets , because I’ve never seen one - they don’t occur in Massachusetts, where I live.
OK, that’s enough to get you started; please do feel free to ask lots of questions!