Friday, September 16, 2016

Another mosaic

My second mosaic dragonfly in September; actually my second ever and my first in Michigan.  My photo views are limited, but I had help from Darrin O'Brien to clinch the identification.  

Above and below:  I've learned the mosaic dragonflies are best identified from photos with a side view which I was unable to get of this perched dragon.

Above and below:  later in the morning I found this mating pair and it was actually the photo below from which Darrin was able to make the ID.

Lance-tipped Darner (Aeshna constricta)

I found the email comments from Darrin below helpful.  Just goes to show how tricky dragonflies can be to identify and how careful one must be.  

The male claspers are paddle-shaped which eliminates some of the more confusing Aeshnas.  This would be much easier to see with a side view.

The pattern at the top of the hind area of the thorax would lead me to believe it's a Lance-tipped Darner (A. constricta).

The abdomen is also constricted, but I don't always find this helpful.

Many times a side view of the thorax is best for ID, but this isn't foolproof.  In this case, if you have a side view of the thoracic stripes, it should clinch the ID.

With many dragonflies, even dorsal, lateral, and ventral photos aren't enough for ID.

I found these Lance-tipped Darner's at Lake St. Clair Metropark along the path between the nature center and the boardwalk area on Sunday, September 10th while leading a DAS birding trip there.  They seemed numerous flying over the path at the start of the walk around 8:15 am - 9:00 am.  When the walk ended around 11:30 am or so, I went back and saw hardly anything.  This is when the mating pair showed up and perched.

No comments: