Bitter Lake is located just northeast of Roswell, NM. The refuge protects a special area because it contains fresh, spring, and salt water areas. Due to this, the refuge attracts both dragonflies and birds that you would usually only see in other saltwater environments, typically along coastlines. Over 100 species of dragonflies and damselflies can be found at the refuge. and during our tour we saw several species including Seaside Dragonlets, Bleach Skimmers, Desert Forktails, and Familiar Bluets. Twelve-spotted skimmers were also around, but we didn't see one up close. The picture at the top is an Eastern Pondhawk that we saw at Gators and Friends Alligator Park and Exotic Zoo in Louisiana, but can also be found at Bitter Lake NWR.
We learned that one way to tell dragonflies and damselflies apart is by their eye structure. Dragonflies have eyes on the top of their head while damselflies have eyes on either side of their head, giving them a "hammerhead" look. Below is a picture of Familiar Bluets and you can see that their eyes are on either side of their head:
To learn more about dragonflies and for some really nice pictures, "A Dazzle of Dragonflies" by Forrest Mitchell and James Lasswell was recommended to me. I also own this book and bought it because I loved the images.
If you are interested in identifying dragonflies and damselflies yourself, there are some great guides coming out. I had a chance to look at "Damselflies of Texas: A Field Guide" (Texas Natural History Guides) by John Abbott and I really liked it.
If you would like a quick reference, I found the following websites helpful:
Dragonflies: http://www.rt66.com/~kjherman/odonata/NMdrgnfly.html
Damselflies: http://www.rt66.com/~kjherman/odonata/NMdmslfly.html
Some of the links in the above sites no longer work and these are for New Mexico, but websites exist for many states.