Tuesday, September 19, 2017

Sedge Darner at Mount Baker

A couple weeks ago, Betsy and I went to Mount Baker to enjoy the scenery and dragonflies. It was 93 ˚F that day, but quite pleasant with the thin air at an altitude of 4200 ft. What a wonderful day. Here are a couple pictures of Mount Shuksan as viewed from Picture Lake.

As we walked along the trail that circles Picture Lake, we saw a number of dragonflies and damselflies. I'll tell you more about them later, but for now I want to focus on one particular dragonfly that turned out to be quite interesting.

At one point we noticed a Ringed Emerald fly to a pine tree and land in the bright sun. As I approached the tree, however, I noticed another dragonfly that was already perched in the same tree, just a few inches away from the emerald. It was a darner, and it was perched deep in the shade of the tree—which is unusual for the darners I'm familiar with, even on a hot day. I realized it was an interesting species because it had simple appendages and blue spots on the tenth segment of the abdomen. I got a few pictures before it flew off, and looked forward to doing some research on them when I got home.

Here's the darner perched in the tree:

After doing a bit of research I realized I had a Sedge Darner, the first of that species I've seen. The simple appendages, blue on S10, and bold thorax stripes all point to that species.

One additional field mark stood out, however—the yellow dorsal stripe on S2. That was quite unexpected. You can see it a bit better in the following enlargement:

I've checked other photos of this species, and the yellow dorsal stripe seems to be a reliable field mark for this species. Here's a photo from the University of Puget Sound of a Sedge Darner specimen:

Here's a different specimen from the same collection:

Other photos online also show this feature, though none of the field guides mentions it at all. Just one more interesting case to add to the various dorsal stripes on S2 that have been pointed out previously in this blog.

Subarctic Darners also have yellow dorsal stripes on S2, but their thorax stripes are quite different from those on the Sedge Darner.

Friday, September 15, 2017

The Whisperer Speaks Again!

I'll be giving a dragonfly talk tomorrow morning at 10:00 am at the Langely Library in the cute little town of Langely, Washington on the southern tip of Whidbey Island. Here's the library:

I hope you can join us—it should be a fun event.

Dorsal Stripes on Darners

Note: This is a re-post of a study I did on the dorsal stripes of various darner species. I'm posting it again now for a couple reasons: (1) I discovered an interesting dorsal stripe on the Sedge Darner, and I'll post details on that soon. It will be useful to compare this new field mark with the ones discussed below. (2) This topic is unique to my field guide, as are a number of others, like splash-dunk/spin-dry behavior. I'm glad to have these new features of dragonflies and their behavior available to a wide audience.

Here's the field guide:

Here's a link to the book on Amazon:

Link to Amazon

Dorsal Stripes on Darners

Field marks are the bread-and-butter of birding and dragonflying.  Having a good suite of field marks for a particular species is important in accurate identification, because a single field mark can be variable or hard to see in a particular situation.

For example, when identifying Hutton's Vireo it's useful to keep in mind a variety of good field marks that distinguish it from the Ruby-crowned Kinglet.  The vireo has light-colored lores, wing bars that lack a dark border, and black feet (as opposed to the yellow feet of the kinglet.)  It's common for only one or two of these field marks to be visible on a given individual as it hops from branch to branch in the bushes, so having a number of field marks to work with can be quite helpful.

With that in mind, a similar situation occurs when identifying certain darners that are quite similar in appearance.  For example, Paddle-tailed Darners (Happy-face Darner) have blue spots on S10, whereas Shadow Darners lack those blue spots.  The tenth segment of the abdomen isn't always easy to get a look at, and so other field marks are useful, like a strong facial line in the Paddle-tailed Darner that is lacking in the Shadow Darner.

Another field mark that I find to be useful for a number of different darners is the blue stripe that appears on the dorsal surface of S2.  For orientation, the "wasp waist" in male darners is S3, and S2 is the bulbous segment closer to the thorax.  Here is a photo comparison of the dorsal stripe in four different, but similar-looking darners.

A comparison of blue dorsal stripes on four different darner species.  The stripes vary from thin and straight to broad and spindle shaped, to half a stripe, to a stripe that is wider at the base that the top.

In the Paddle-tailed Darner, the blue dorsal stripe is straight, thin, and fairly uniform.  In the Shadow Darner it is broad and spindle shaped – almost like a bishop chess piece.  Only half a stripe appears on the Variable Darner, and Walker's Darner has a stripe that is wider at the base than at the top.  I need to work more on these to see how consistent they are, and how they can be extended to other species as well. (Note: Further study of these field marks shows that they are indeed quite useful.)

Here's a gallery of photos showing these darners.  Check out the dorsal stripes as an additional means of identification:

Paddle-tailed Darner (Happy-face Darner).  Note the thin, straight, uniform dorsal stripe on S2.

Again, a nice Paddle-tailed Darner (Happy-face Darner).  You can't see S10 in this photo, but the dorsal stripe on S2 is quite definitive.

A triplet of free-range darners.  From lef to right we have Shadow, Shadow, Paddle-tailed.  These dragonflies were never captured – simply lifted one at a time onto my fingers.  They were free to fly away at any time.

A Shadow Darner shows off his broad dorsal stripe on S2.

Two free-range Shadow Darners.

A Variable Darner sports just half a stripe on S2.

Walker's Darner has a dorsal stripe on S2 that is wider at the base than at the top.

A closer look at the dorsal stripe on S2 for a Walker's Darner.

I've enjoyed using this field mark, and will continue to apply it and test it out for consistency and dependability. (Note: In a coming post I will point out the interesting dorsal stripe on S2 in the Sedge Darner.)

Wednesday, September 13, 2017

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.

Tuesday, September 12, 2017

Forest Fires And "White Spots" On The Hudsonian Whiteface

I'm often asked about the "white spots" that are seen on the eyes of dragonflies. Here are a couple examples of these "white spots" on the eyes of male Hudsonian Whitefaces:

The "white spots" are reflections of the sun, and these pictures were taken on clear, sunny days. In addition, the second picture clearly shows the whitish wing tips characteristic of whitefaces.

The next photo shows a pair of Hudsonian Whitefaces in the wheel position at Beaver Pond in Winthrop, WA. Notice that the "white spots" on both the male and female are subdued in intensity, and distinctly orange in color.

Here's a closer look at the sun's reflection on the male's eye:

The reason for the orange "white spots" is that on the day we visited Beaver Pond there was a great deal of smoke in the air from forest fires in British Columbia. This resulted in the sun being reduced in intensity, and distinctly orangish in color. This is the first time I've had pictures showing "white spots" that are actually orange.

You can find a discussion of "white spots" in my new field guide, Common Dragonflies and Damselflies of the Pacific Coast, shown below.

Here's a link to the Amazon page:

Amazon Link

You will also find a discussion of the whitish wings tips of whitefaces in my field guide. As far as I know, other field guides don't mention this feature, but it is a useful field mark and interesting to observe with binoculars.

Thursday, September 7, 2017

The Whisperer Spoke—And Speaks Again Tomorrow!

Betsy and I gave a dragonfly talk yesterday evening at the Anacortes Library. It was a lot of fun, and thanks to all who attended for your enthusiastic response.

Tomorrow evening we give another talk at Village Books in Bellingham. Here's an ad for the event:

I hope to see another large group of dragonfly enthusiasts for a fun and educational evening!

P. S. Here are a couple photos from the eclipse at Volcanoes Stadium last week.

The top photo shows a series of partial phases plus totality by professional photographer Ben Ammon. The lower photo is from Sports Illustrated showing the Volcanoes ballplayers—one of whom is viewing the partial phase of the eclipse—wearing their special eclipse-day jerseys. What an experience!

Tuesday, September 5, 2017

New Field Guide: Sample Spread

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 Blue Dasher.

Blue Dashers are one of the most common dragonflies in our area, and also one of the most photogenic. They perch all the time, repeatedly returning to the same perch and assuming wonderfully graceful poses. Look for these delightful insects at your local pond or lake, and you'll have a lot of fun getting some very nice photos!

Each species has its own spread like this one for the Blue Dasher, 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 Blue Dasher 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. For example, we can see that about 60% of all observations of Blue Dashers occur in the months of June and July.

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 Blue Dasher spread are blue. 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!