Sunday, October 5, 2014

Eight-spotted vs. Twelve-spotted Skimmer

One problem with Montana is that  its almost impossible to drive across and search for birds and dragonflies at the same time. I have a favorite rest area where Interstate 90 crosses the Madison River near Three Forks in Gallatin County. This spot is not an official rest area, but a fishing access off the frontage road on the north side of the Interstate.

Despite windy, chilly conditions on 17 July 2014, a few dragonflies chased each other above cattail-edged pools. At first I thought these were Twelve-spotted Skimmers, like the one in the second photo from the Lebanon Hills Regional Park near Minneapolis (photographed in July 2013). But they appeared a bit odd. The wings seemed short, maybe because they lacked terminal black spots. The white spots on the hind wings blended together. The abdomens appeared very bright blue-gray.

All dragonflies should be so easy to identify! These odes were my first Eight-spotted Skimmers. This dragonfly is found across much of the western United States, east only to Colorado and Wyoming. The skimmer was difficult to photograph until one repeatedly returned  to a nearby perch. Paulson (2009)describes this behavior well, saying they "move constantly, not defending fixed territories…[showing] much aggression to other males of their own and other similar-sized species."

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