18 January 2012

Review: Dragonflies and Damselflies of the East

If you live in the eastern United States or Canada, be sure to pick up a copy of Dragonflies and Damselflies of the East by Dennis Paulson. This book is a must for any odonata enthusiast.

It covers 336 species in 538 pages. Some of these are the same species Paulson covered in his earlier release, Dragonflies and Damselflies of the West. If you own that book, you may want to pick up the eastern guide anyway; Paulson notes in his preface that in the two years or so since the western guide was published he has learned so much that some material in the eastern guide will "modify, perhaps even contradict" the previous book.

That caveat reflects how rapidly our understanding of Odonata distribution, ecology, and identification is evolving. Putting together a field guide to any taxa is a daunting task, much less authoring one on a moving target like Odonata. Paulson has pulled together reams of data from many sources to make this book an essential step forward from the first broad field guide to Odonata, Dunkle's Dragonflies through Binoculars, published in 2000. And of course, unlike Dunkle, it contains damselflies -- a huge and exciting plus.

Field use

Although it is in a standard roughly 8.5 by 5.5 inch field-guide size, it will weigh down your field pack by 2 pounds, 5 ounces. The type size doesn't seem smaller than other field guides, but it is very dense -- a lot of text with characters spaced very closely. For those of us in middle age, it can be difficult to wade through, especially in the field.

There are two aspects of the layout that could make field use a bit frustrating from some people.  Although we strongly prefer photo/illustration, text, and maps for each species to be all together (as they are in this book) rather than separated into plates and text (as they are in Dunkle), the variable amount of material for each species in this book means a species account could start anywhere on a page. You have to scan each page for the name of the species you are looking for. This layout is unavoidable given the amount of material in the book; thoroughness won out over user-friendly.

Second, the species are arranged in taxonomic order. In most lists of Odonata (including the Checklist of North American Odonata1), the species are listed in alphabetical order within each genus. Perhaps for most folks, who don't know the scientific names of many odonates in the first place, this will start them out on the right foot: learning the correct order and relationships. For those of us who know just enough Latin to be dangerous, it just sends us to the index. Putting together a quickie index to paste inside the back cover to guide you to your most frequently-used genera/species will be helpful.

Introductory and background material

A good introduction reviews Odonata natural history and anatomy with many great photos adding to the text.  Paulson writes clear prose that is easy-to-read without dumbing down, technical and accurate without being pedantic, and which shows his enthusiasm and wonder for odonates. The detailed macro anatomy photos in this section will be extremely helpful to complement the text describing each species, as will the three-page glossary in the back of the book.

Other overview material includes odonate threats and conservation; and finding, photographing, identifying, and collecting Odonata. Paulson outlines the important elements of identification, emphasizing the many pitfalls of trying to ID odes in the field or from photos, and he provides a good section on the hows and whys of collecting voucher specimens.

Species accounts

As one would expect, the majority of the book contains the species accounts. Each species is given similar attention, whether it's widespread and common, or limited in range. Topics for each include identification, similar species, natural history, habitat, flight season, distribution, and a range map. There are typically at least two photos in each account, usually one of each sex but also sometimes various color forms, young individuals, or regional variants.

One of the best features of the book are the illustrations which show differences between similar species' features such as male appendages or female subgenital plates. These usually follow the group of species accounts that they illustrate (pond damsels, common clubtails), but sometimes occur within the species accounts (e.g., some male Aeshna hamules and appendages). We find illustrations like this essential to ID, providing you have the insect in hand (we'd love to have these illustrations included in a small booklet for the field). These are some of the largest and most helpful we've seen, especially helpful since while the photographs of each species are very nice, most cannot adequately portray these key features. Note, however, that the illlustrations are all simple, clear line drawings and depict structural differences. Thus, no page of thoracic patterns of darners, or color patterns of the last few abdominal sections of bluets or dancers. The line drawings are only labeled with common names; scientific names would have been a valuable inclusion, and it seems like space is adequate.

While we haven't read each one, the text for the accounts seems more than adequate. Regional differences are noted if needed. The "Comments" section is often the most interesting, providing information on taxonomic quandaries, distribution mysteries, and/or knotty identification problems. It's worth it to read the introductory material for each genera as well as the accounts of all similar species when you're attacking an ID to get a complete picture. For instance, the account for Slender Baskettail (Epitheca costalis) mentions the intermediate/hybrid individuals (with Common Baskettail, E. cynosura) in the upper Midwest, but this is not brought up in the cynosura account -- even though that account notes it is the most common baskettail in the east with which all others should be compared.

The range maps are not color-coded to indicate early or late flight seasons. That was a nice touch in Dunkle's book, but would have added another layer of complexity to an already complicated task. Constructing range maps for a large region is fraught with pitfalls. These are based on a wide variety of sources and include data through the year 2010. But with a taxa like Odonata where our knowledge of distribution is so dynamic, they should be used, as Paulson notes, to "give a good idea of the known or expected distribution." He provides a further caveat that some records on which the maps are based are old, and some species may now be absent for parts of their former range.

At this particular scale, some range margins need to be taken with a grain of salt. For instance, Flag-tailed Spinyleg (Dromogomphus spoliatus) was first found by us in Michigan in Wayne Co., and has since been found in Monroe and Lenawee counties, all in extreme southeastern Michigan. The range map seems overly generous for the state. We had Michigan's first Band-winged Dragonlets (Erythrodiplax umbrata) in 2007. The record is in Odonata Central, and was published within months, but the range falls short of Michigan (nor is there a dot indicating a vagrant record). And although it was axed from the MOS database -- but not from Odonata Central -- years ago as an error, the Alpena County Russet-tipped Clubtail (Stylurus plagiatus) is shown on its map. It's just not possible for an author to keep up with all of this, and the range maps are surprisingly detailed given the amount of fragmented source data. They are a great jumping off point...and let the errata compilation begin!

In fact, the Princeton University Press web site includes a link to references used in both the eastern and western guides. It only includes papers published through 2007, but will be added to and become a valuable go-to site for serious users wanting updates.

This guide is also available in a Kindle edition. We'd be interested in hearing from people who have this on a Kindle Fire or other color e-reader. How does it look and function?

Our job as reviewers is to critique. Many of our comments are nit-picky, and probably won't be too important to the average user of the book. Though we have critiqued, we are not critical of this absolutely essential book. Get it, study it, and be ready for ode season 2012!

1Paulson, D. R., and S. W. Dunkle. 2011. A Checklist of North American Odonata, Including English Name, Etymology, Type Locality and Distribution. 2011 Edition. Originally published as Occasional Paper No. 56, Slater Museum of Natural History, University of Puget Sound, June 1999; completely revised March 2009; updated February 2011.