Tuesday, March 20, 2018

Common Dragonflies and Damselflies of the Pacific Coast

Here's the cover of my new dragonfly field guide.

The guide has a nice feel to it, due in part to the high quality paper that we used, but also to the size and shape of the book that allows it to fit nicely in the hand or pocket.

Here's a peek inside the guide, at the spread for the Comm Green Darner, the subject of the previous post.

Each species has its own spread, and each has a number of helpful features:

• Life Size Photo
• Range Map
• Flight-Season Chart
• Annotated Photos
• Colored Margins

Here's a brief description of each feature:

Life Size Photo (A unique feature in this guide) Dragonfly field guides generally give a numerical value for the size of a dragonfly species. This is fine, as far as it goes, but what's even better is to show the dragonfly at life size right there in the guide. The photo on the left side of the Common Green Darner spread shows the dragonfly at life size—as if it had actually landed on the page. Now you know exactly how big it is.

Range Map The range maps in this field guide are derived from dots maps produced by the Dragonfly Society of the Americas (DSA). The observations in the maps are vetted by dragonfly experts, and provide the current state-of-the-art in our knowledge of dragonfly ranges.

Flight-Season Chart (A unique feature in this guide) The DSA dot maps have dates associated with each observation. I have "data-mined" this information to produce charts that show the percentage of observations for each month of the year. The charts give not only the beginning and ending months of the flight season, as in many guides, but also the distribution of sightings within the season.

Annotated Photos (A unique feature in this guide) It can be hard when you start to do some dragonflying to know just where to find the relevant field marks of a particular species. In this guide, each species has annotated photos that point out exactly where the key field marks are and how to interpret them.

Colored Margins The margins of each spread have a color that is most characteristic of that particular species. Thus, the margins on the Common Green Darner spread are green. By looking for the appropriate color on the margins of the pages you can quickly locate the section where the dragonfly you want to identify is located.

The guide also includes detailed information on dragonfly behavior, and I'll describe some of those features in future posts.

Here's a link to the Amazon page for the book:

Link To Amazon

It's been a lot of fun writing this book, including as it does so many of my favorite photos and new observations of dragonfly behavior. I sincerely hope it will be helpful in introducing others to the pleasures of dragonflying!

Monday, March 19, 2018

Species Spotlight: Common Green Darner

The next species in the spotlight, the Common Green Darner (Anax junius)—which is closely related to the previous species, the Comet Darner (Anax longipes)—has the distinction of being the official state insect of Washington state. It is a large, vigorous dragonfly that is widespread across North America, and is one of the species of dragonfly known to migrate. Its scientific name means "King or Ruler of June" referring to the peak of its flight season; the scientific name for the Comet Darner means "Ruler with long legs" which is certainly an apt name as can be seen in the photos for that species below.

You can judge the size of this species from the following photo, showing a mating pair that I whispered onto my finger.

One day we saw a male Common Green Darner catch and consume a female Eight-spotted Skimmer—which is a good-sized dragonfly in its own right.

Here's a pair of Common Green Darners in tandem, as the female lays eggs in a floating log. Sometimes the female will go partly underwater—up to her thorax at least—as she probes for a suitable deposition site. Notice also the yellow veins on the leading edge of the wings.

The following shot shows a freshly emerged teneral female Common Green Darner. The colors are bright and fresh, and her body is partially translucent.

Common Green Darners are always a delight to see as they whiz by at high speed. Seeing one perched so you can get a close up look is an added bonus.

Wednesday, March 14, 2018

Species Spotlight: Comet Darner

When we visited Virginia a couple years ago, we were delighted to come across Comet Darners for the first time. These are large, impressive dragonflies, with bold red and green colors. Here's a male perched in a tree:

Notice the bi-color pattern on the body—bright red on the abdomen, dark green on the thorax and head. This is similar to the bi-color pattern of the Common Green Darner, though in that case the abdomen is blue. Not surprisingly, these two species are in the same genus. The Comet Darner's scientific name is Anax longipes, while the scientific name of the Common Green Darner is Anax junius.

Here's another look at the Comet Darner, this time with a bit more of a side view.

Take a look at the long, robust red legs. Quite impressive. I'm sure this dragonfly is an aggressive hunter, and one that is capable of grappling with large powerful prey.

Friday, March 2, 2018

Species Spotlight: Variable Darner

Darners are large, conspicuous dragonflies. The species in the spotlight today, the Variable Darner, is even more conspicuous because it has a penchant for landing on vertical surfaces—like fence posts, walls, tree trunks, and people. It is not a particularly common species, however, at least in the northern Puget Sound area. We generally see only a few each year.

The most distinctive field marks for the Variable Darner are the "pinched in" side stripes on the thorax. The stripes are narrower in the middle than at either end, and sometimes "pinch off" entirely to leave a spot at the top and bottom where the side stripe would normally be on other darner species.

The Variable Darner has minimal to nonexistent front stripes on the thorax. In addition, the blue line on top segment 2 of the abdomen is generally incomplete—it starts from the rear of the segment, but only goes about halfway toward the front of the segment.

The tenth segment of the abdomen is cream colored in Variable Darners, and the appendages are simple—that is, they taper smoothly to a point.

Wednesday, February 28, 2018

Species Spotlight: Western Pondhawk

The next species in our spotlight is the Western Pondhawk—a common dragonfly all up and down the Pacific coast. It's range extends eastward into Texas in the southern part of the USA.

Mature males of this species are a wonderful powder blue color—though they start off life a brilliant green. With age they turn blue from the tip of the abdomen forward. Females also start off green, but they retain their green color for life, making them the only mature green dragonfly on the Pacific coast.

This dragonfly loves to perch on the ground—which it almost always does unless the ground is covered with vegetation. It also seems to specialize in eating damselflies; at least, when I see them eating prey, it's usually a damselfly.

Also, be sure to look for the "Groucho Marx" mustache on the face of this species. It's quite distinctive, and is often seen on females as well!

For more information, see Common Dragonflies and Damselflies of the Pacific Coast:


Monday, February 19, 2018

Cherry Springs Interpretive Sign

Note: Over the years, this post from September 4, 2013 has been one of the most popular on the blog. I thought I would re-post it so more people will have a chance to see what it's all about. I still hope to get to Cherry Springs Nature Area one of these days.

Not long ago, I was contacted by naturalist Sheri Covert at the Cherry Springs nature area near Pocatello, Idaho.  She was putting together an interpretive sign to inform visitors about some of the interesting insect life to be found there, and asked if she could use a couple of my dragonfly pictures.  I was happy to help with a project like that, and supplied her with pictures of the species she was looking for.  Here's a rough draft of the sign, which looks very nice.

Here's an enlargement of the dragonfly section:

I look forward to visiting Cherry Springs one of these days.  If any of my intrepid readers gets there first, please take a picture of the sign in place and we'll include it in the blog.

You can learn more about the species featured on the Cherry Springs Interpretive Sign in my new field guide, Common Dragonflies and Damselflies of the Pacific Coast. You can see more about it at the following link to Amazon:


P. S. They have a very good price for it right now!

Saturday, February 10, 2018

Auricles—Mystery Structure

The previous post, on the Columbia Clubtail, brought to mind an enigmatic set of structures of male dragonflies referred to as the auricles. The reason for the name is that the shape of auricles in some species is vaguely ear shaped. The function of the auricles is unknown at the moment, though the best guess is that they may assist the female as she tries to find the hookup point for mating.

Be that as it may, the auricles on some species are quite striking in shape and color. One such case is the Columbia Clubtail. The next two photos point out the auricles on a male Columbia Clubtail:

The auricles in this species are bright yellow, contrasting with the pruinose blue abdomen, and shaped like little tennis balls.

Here's another clubtail species, the Pacific Clubtail, which also has prominent yellow auricles.

Closely related to the clubtails is the Grappletail—also with prominent yellow auricles:

In darners, the auricles are more ear shaped, and not quite as prominent—though they do have a nice blue color. Here's an example in the Shadow Darner:

Here's another view, this time in a Paddle-tailed Darner:

Next is a view of the underside of dead Paddle-tailed Darner we found at Cranberry Lake.

Notice the little "hooks" along the edge of the auricles. What is their purpose?

In contrast, here is a similar view of a female darner, showing the lack of auricles:

All in all, the auricles are a mysterious feature of male dragonflies. Maybe one of these days we'll get to see these structures in action—that would be fun.