Thursday, March 29, 2018

Species Spotlight: Common Whitetail

The next species in the spotlight is another "common" species—the Common Whitetail. Here's a look at the male of the species:

Notice the brilliant white abdomen—the origin of its common name. The abdomen is wider and flatter than in other species, to show it off to best effect; the underside of the abdomen is black. The white color is the result of pruinosity, which is also visible near the base of the wings. Speaking of the wings, the large black patches are another prominent field mark for this species—as if any additional field marks were needed.

This species generally perches on the ground, when bare areas are available. Here's another example:

Males chase one another back and forth along the shoreline incessantly, and in a very particular way. The pursued male depresses his abdomen to shows its white surface to the pursuer; the pursuer raises its abdomen to show the white surface to the male it's chasing.

Females of this species have small dark spots in the wings, similar to those in female Eight-spotted Skimmers and female Twelve-spotted Skimmers. A key difference, besides the number of black spots in the wings, is that the side stripes along the edge of the abdomen are straight and yellow in the Eight-spotted and Twelve-spotted Skimmers, whereas all but one are white and curve inward at the forward end in the Common Whitetail. This can be seen clearly in the photo of a female Common Whitetail below.

For comparison, here's a female Eight-spotted Skimmer, with her straight, yellow side stripes:

The abdomens of Common Whitetails are so stout and thick that it is difficult for them to maintain the wheel position; therefore, mating is very brief. In addition, it's hard for them to remain attached in tandem, and hence the female lays eggs by herself as the male hovers above her to ward off any intruders.

All in all, the Common Whitetail is a beautiful dragonfly species with lots of interesting behavior to observe. Read more about this and other species in my new field guide, Common Dragonflies and Damselflies of the Pacific Coast.

Monday, March 26, 2018

Vitruvian Tattoo

I just had a request from a da Vinci/dragonfly enthusiast to use the Vitruvian Dragonfly, shown below, for a tattoo.

That should be interesting. I'm curious to see the final result.

The above is a polished piece of art by Sabine Deviche from my original concept shown below:

She also made the following full color version:

I think they're both fantastic.

You can find more of Sabine's wonderful artwork at her website:

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.