Friday, October 19, 2012

A Darner In The Bush Is Worth Two In The Hand

A couple days ago there was a brief break in our autumnal rains, and I took advantage of it by zipping up to Cranberry Lake for a few minutes.  It was cool there, 55 ˚F, and breezy – only a bit of sun filtered through the clouds.  Still, five or six darners were flying over the water and checking for females along the shoreline.  In addition, six or seven darners were perched in the bushes, perhaps hoping for a little more sun, and a few Autumn Meadowhawks were perched on the ground.

I decided to do some dragonfly whispering.  I went up to one of the Happy-face Darners (Paddle-tailed Darner) in the bushes and lifted him onto my finger.  Remember that this was a "free-range dragonfly", completely free to take wing at any time.  It had never been caught or manipulated in any way – I simply lifted it up on my finger, which took the place of a branch.  Here's what he looked like as he sat happily on my hand.

A male Happy-face Darner (Paddle-tailed Darner) resting on my hand.  Such a charming fellow.  (The white spots on the eyes are reflections of the Sun.)

Here are a couple more photos of him.  If you toggle back and forth between the photos you'll get an idea of what it looks like as he cocks his head.

After the darner flew off to go about his busy day, I decided to lift another Happy-face Darner onto one finger, and then while he was going along for the ride, lift a Shadow Darner onto a second finger.  This makes for a nice comparison between these two similar species.  Again, remember these are "free-range dragonflies".

A male Happy-face Darner (Paddle-tailed Darner) on the left, and a male Shadow Darner on the right.  The Happy-face has blue on the tenth segment of its abdomen, but the Shadow Darner's tenth segment is black.  In addition, the blue spots are large, and actually get a bit larger, as you go toward the end of the Happy-face abdomen.  In the Shadow Darner, the blue spots get smaller and eventually disappear altogether.

Here's another view.  In this case, notice the top of segment 2 of the abdomen.  For orientation, segment 3 is the one that is narrow – almost like a wasp waist.  Segment 2 is the large, bulbous segment that is closer to the thorax.  On the top of this segment, the dorsal surface, there is a blue stripe in both species.  The blue stripe on the Happy-face Darner is thin and uniform in width.  In contract, the blue dorsal stripe on the Shadow Darner is broad and nonuniform.  It looks a bit like a chess piece, or the profile of a tree.

Happy-face Darner (left) and Shadow Darner (right).  Notice the difference in the blue dorsal stripe on segment 2 of the abdomen.  It is thin and uniform in the Happy-face, broad and nonuniform in the Shadow.

The blue dorsal stripe on segment 2 is a field mark that I haven't seen mentioned in any of the field guides, but I find it quite helpful.  I often see a darner in the bushes, and a leaf blocks a view of the tip of the abdomen.  No worry – if I can see segment 2 I'm in business.

1 comment:

  1. I love your pictures, they are really great. The dragonfly looks soo happy.