Saturday, May 12, 2012

My first northwest odonates of 2012

...and I specify “northwest” because I had been traveling in Louisiana and South Carolina the last few weeks and I saw lots of odonates during that time. See my previous three posts for a taste of what I saw in Louisiana; I’ll try to put something together on the highlights in South Carolina during the Dragonfly Society of the Americas annual meeting there.

Yesterday—my first full day back in Vancouver, Washington, after returning from South Carolina, I visited some ponds in the Burnt Bridge Creek Greenway. I only started visiting these ponds a couple months ago, so it’ll be interesting to see what the odonate fauna is like as the season progresses.

I saw a total of five species yesterday—three damselflies and two dragonflies. In addition to what I describe below, I saw a single Common Green Darner (Anax junius) fly a couple of circuits around one of the ponds. Here are the other four species:

Pacific Forktail (Ischnura cervula)
I was determined to photograph the very first odonate I saw and this male Pacific Forktail (Ischnura cervula) was the lucky winner. I ended up seeing many, many individuals of this species—many of them mature like this one, and many that had just emerged. This must be the most photographed odonate on my blog, but it is a very common and widespread species in the region.
Western Forktail (Ischnura perparva)
I only saw a few Western Forktails (Ischnura perparva), maybe a couple males, like the the above, and one female—all mature. Note the complete stripes on top of the thorax rather than the isolated spots on the Pacific Forktail above. Also the pale areas of the thorax are distinctly green rather than blue, which was how I initially picked out this individual as it was flying low over the water (some are pale blue rather than green).
Tule Bluet (Enallagma carunculatum)
I only saw a few Tule Bluets (Enallagma carunculatum) and all were teneral (recently emerged) like the male above. Over the next few days the cuticle of the exoskeleton will harden completely, the cells of the wings will become more clear while the veins darken, and the light brown areas of the body will turn pale blue. This is a very common species in this area and it won't be long before many more are on the wing.
Things can take a turn for the worse when an odonate flies into a spider web like this teneral Tule Bluet did, however this individual was lucky. While photographing it, I realized that it was still kicking and that a spider had not gotten to it—this must have been an old, unoccupied web. I was able to free the little guy without damaging the fragile wings and he quickly flew away.
This damselfly was well beyond saving. I believe it was an immature female Pacific Forktail (Ischnura cervula).
California Darner (Rhionaeschna californica)
I eventually saw a few California Darners (Rhionaeschna californica) flying around, but this exuvia (the shed skin of the nymph left behind after emergence) on an old cattail stem was my only photographic evidence.
Here is that same California Darner exuvia posed nicely on a boulder for a clearer view. Darner nymphs and exuviae are easily sexed, and this was a female.


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