Tuesday, February 18, 2014

Common Dragonflies of Anacortes: The Three Amigos!

Anacortes is a great place to dragonfly.  It's where the Happy-face Darner was discovered – at Cranberry Lake on October 22, 2006 – and where splash-dunking was first filmed.  In addition, the previously-unknown phenomenon of spin-drying was also discovered at Cranberry Lake.  All told, something like 25 species of dragonflies and damselflies have been seen in Anacortes.

If you see a red dragonfly in Anacortes, you know for sure that you've just seen a meadowhawk.  Similarly, a yellow dragonfly is a freshly-emerged – that is, a teneral – meadowhawk.  To summarize:

red dragonfly = meadowhawk
       yellow dragonfly = teneral meadowhawk

There are three meadowhawks that are most common in Anacortes – the three amigos.  They are, in order of flight date, the Cardinal Meadowhawk, the Striped Meadowhawk, and the Autumn Meadowhawk.  The meadowhawks and their flight seasons are shown below:

The above histograms show the flight season of each meadowhawk in terms of the percentage of observations.  For example, roughly 40% of all observations of Cardinal Meadowhawks occur in July, and about 20% occur in August.

From these histograms, you can conclude that if you happen to see a red dragonfly in May, it is a Cardinal Meadowhawk.  A red dragonfly in June is almost certainly a Cardinal Meadowhawk.  In July and August, a red dragonfly could be either a Cardinal Meadowhawk or a Striped Meadowhawk.  In October and November, red dragonflies are almost certainly Autumn Meadowhawks.  In general, the shift in flight season is quite apparent from the shift in the peaks of the histograms.

There is a similar shift in the range maps of these species as well.  This can be seen in the maps shown below:

Notice that the Cardinal Meadowhawks are primarily a western species.  The Striped Meadowhawk go roughly from the west coast to the Rockies.  On the other hand, the Autumn Meadowhawk is primarily as eastern species, with just a relatively small enclave on the west coast.

Thursday, February 13, 2014

A Happy-face Rogues' Gallery

Over the years I've taken literally thousands of photos of the Happy-face Darner (aka, the Paddle-tailed Darner).  Here's a small sampling:

The two photos on the bottom right of the grid were taken on the deck in our backyard.  All of the rest were taken at Cranberry Lake, where we see the Happy-face Darner all the time in the late summer and early fall.

The photo in the center is still my favorite.  In fact, it was the first one I ever took of the Happy-face Darner, on October 22, 2006.  I reached into the bushes with my camera and took a shot of a dragonfly perched there without even looking at the viewfinder.  When I loaded the photo onto my computer at home I was amazed, and I called to Betsy.  "Take a look," I said, "this dragonfly has a happy-face!"  This discovery launched my interest in dragonflies, which has given me great pleasure ever since.

The following quote from Henri Poincaré summarizes my feelings about science and nature quite well.

I might add to this thought, however, that the scientist also delights in nature because it is infinitely intriguing and surprising – just take the Happy-face as an example!