Odoonata: Learning to identify
While I am still struggling to identify all the beautiful species of Odonata around me, with particular emphasis on dragonflies and damselflies in my county (Bladen County, NC) and on my property, I wanted to take a moment to document the resources I'm using and some ways I've used to try to reduce my confusion.
My number one resource has been the NC Odonate Website at https://auth1.dpr.ncparks.gov/odes/a/accounts.php
This website is fantastic with one caveat: you sort of need to know which Odonate you're looking for so you can do a search for that species. The species accounts are excellent and you can click on a county and see where others have seen the particular species you may be interested in. You can also get a list of the species in a specific county. So I was able to get a list of the species I might be able to find in Bladen County.
Field Guides are also essential and I've found the following to work the best for me:
- "Dragonflies and Damselflies of the East" by Dennis Paulson
- "Dragonflies & Damselflies of Georgia and the Southeast" by Giff Beaton
- "Dragonflies of Texas" and "Damselflies of Texas" by John C. Abbott
That last one may not appear to be useful for other states in the USA but between the two volumes, it contains most of the Odonata (although not all) found in North Carolina and the format is fantastic. Each species gets two pages with one page devoted to photos or illustrations of the creature and the other page listing identification, similar species, status, habitat, and a discussion for the species. There is also an illustration that is the approximate actual size, which is very helpful for me (I have trouble with size).
There are also excellent comparative pages of the male appendages of various species in a genus as well as female appendage comparisons (which actually would require a microscope or good magnifying glass to see well).
I have other Odonata guides as well because each one of these offers slightly different information. No guide is absolutely perfect. None has much (if any) information on tenerals or exuviae although Abbott's books do have more information on immature. The others also have some information on immatures (but immatures and females continue to be a challenge and very confusing for me).
Here's the other thing: folks on iNaturalist have given me tips on identification and in almost all (if not entirely all) the tips have contained gems of information which are NOT found in any of these guides. Good grief! There is so much to learn!
So, in order to help reduce my confusion, I've resorted to the following: I've been creating tables of species that I tend to confuse and include information from all the tips and all the guides so that information is in one location that I can use to help in identification. Here is an example:
| Characteristic | Attenuated Bluet Male | Pale Bluet Male | A.B. Female | P.B. Female |
|---|---|---|---|---|
| Eyes | Blue over green | All blue | Tan, darker above with two brown lines encircling upper half | Light blue over tan |
| Eye spots | Large pale blue spots | Thin black line between eyes | ||
| Head | Almost all pale | Blue | Blue with fine black marks | |
| Thorax | Light blue | Light Blue | Greenish tinged with blue | Light Blue |
| Stripes | Very thin to no black median and humeral; humeral often broken | Narrow black median and humeral | Narrow median and humeral tan stripes with black edges | |
| Legs | Pale | |||
| Abdomen | Black dorsally | Black dorsally | Black dorsally, scarcely any basal rings | Black dorsally with pale sides |
| S1 | Pale blue | Blue | ||
| S2 | Blue on sides | Blue sides | ||
| S3 | Blue on base | |||
| S7 | Blue on distal third, plue extends to tip of S7 | Blue with black stripe on upper surface | ||
| S8 | All blue | All Blue | Blue with black stripe on upper surface | Blue with black basal triangle |
| S9 | All blue | All blue | Blue | Blue, brighter and may be greenish |
| S10 | All blue | All blue | Blue | Blue, brighter and may be greenish |
| Overall | Very long and slender; almost no black on head, thorax, or abdomen tip | Color ranges from light blue to greenish blue or tan | ||
| Behavior | Perches higher than others; hovers |
On some, I'll need to list all the segments (S1 - S10) or even thorax stripes (T1, etc) but this is a way to get the tips and information from all sources integrated into one place. The only downside is the lack of illustrations/photos which are of such enormous assistance in the reference books and web sites.
In the future, what I intend to do is to download and print the species accounts from the NC Odonate Website, add my photos that have been confirmed for that species on iNaturalist (print them), and then add my comparative tables in a notebook to form a guide which will help me. The beauty of this is that it forces me to digest the information in a way that is useful to me so it helps me to learn. And it will eventually give me a reference book that will assist me in my quest to improve my identification skills.
I'm hoping that this may be helpful both to me and to others. It can be done for anything really (plants, etc) that is confusing.
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