Monday, August 5, 2019

Coon Forks - A Cornucopia of Odonata

I have several sites I try to get out to every few weeks.  The point of these repeated visits is to build up long-term data on the population fluctuations, and how they are potentially changing over time.  Coon Forks County Park is likely the most important site that I get out to regularly.  It has several habitats within the park, which allows for an incredible diversity of Odonata. 

My fascination with Coon Forks started on July 7th, 2013 when I was canoeing with my family.  In one of the backwaters, we noticed a large dark dragonfly darting in and out of the tangle of brush along the shaded shoreline.  We paddled up to it and it landed within arm’s reach in a thick woody shrub.  There was no room to net, so I reached out and by some miracle, picked it up.  It was without a doubt a SomatochIora.  I was still relatively new to dragonfly ID, and as many of you know, the species of the genus Somatochlora (Striped Emeralds) are not easy to find and difficult to ID.  I identified this with my handy Dragonflies of the Northwood’s field guide as an Incurvate Emerald.  I was thrilled as this was not only a county record for Eau Claire, but also on the “most-wanted list” on the Wisconsin Odonata Survey site.  Acutely aware that my experience with Somatochlora was limited, my optimism was a little guarded.  I sent the photos to Bob Dubois and he confirmed that I indeed had found an Incurvate Emerald.
I was terribly excited, but soon my science background took over.  The habitat for Incurvate Emeralds is listed as bog pools and open wet sedge meadows, not backwaters of small lakes.  This led me to Google Earth (this is what the internet is really for people) and careful scanning of satellite images.  I found that there was a very large open area in the southwest corner of the park that could very well be a large marsh.  The next year, I hiked in and found the marsh.  Low and behold, I found more Incurvate Emeralds.  Regular visits to the marsh led to many county records and interesting species.  Brush-tipped Emerald, Kennedy’s Emerald, Delicate Emerald, and Ocellated Emerald all have been located in the area to go along with what appears to be a healthy Incurvate Emerald habitat. 

I had also been really hoping to find a site for Ebony Boghaunters in Eau Claire, and the marsh did not disappoint.  I found a pair in tandem there on June 10th 2015.  This led me to visiting the park early the next year to see if I could locate the breeding site; I found many more.   I also discovered a Ringed Boghaunter, which I never hoped to find in Eau Claire County.  Since then I have monitored the populations of these two glacial relict species.  They could provide a window into how climate change might affect some of these isolated and rare populations of animals. 

I went to the park on Saturday (August 3rd) for two main purposes.  To check out the Incurvate Emerald population, and to see if I could find Fawn Darners and Zebra Clubtails at Black Creek, the main inlet for the lake.  I had not observed these two species in the park but suspected they may occur here.

Incurvates were easy to find at the marsh.  I netted several and found a pair in tandem as well.  Mission one was a success!  Meadowhawks were present in huge numbers, which was a welcome counter to the swarm of mosquitoes that accosted me on my early morning walk in along the shaded ski trails.  I also noted one Delicate Emerald, a Brush-tipped Emerald, and a few Green-striped Darners. 

After my marsh foray was complete, I retreated to the lake and traded my waders for my kayak.  The lake backwaters nearing the creek inlet were alive with Odonata.  Black-shouldered Spinylegs, Prince Baskettails, and Common Green Darners dominated the waterscape, along with a large number of Widow and Twelve-spotted Skimmers.  Damselflies were also abundant, highlighted by Variable Dancers and Stream Bluets.  As I neared the creek, Ebony Jewelwings took over the area.  Common Sanddragons were abundant on the sand flats at the Creek mouth, and I was very surprised to find a couple of very late Lilypad Clubtails on the vegetation right across from the creek mouth.  The variety of species for August was incredible!

It took me all of a minute of walking up the shallow sand-bottomed creek to flush a female Fawn Darner.  She was kind enough to land in a tree near the bank and I was able to get a couple of average documentation photos.  A minute farther upstream a Zebra Clubtail landed right in front of me.  Mission two was accomplished in two minutes.  Better to be lucky than good sometimes.

My species tally for the day was 32, which is a phenomenal number for an August survey.  Adding the Fawn Darner and Zebra Clubtail to the list pushes my unofficial Odonate Coon Forks species list up to 76 species.  It is a tremendous location with a variety of interesting habitats.  In one small area, you have marsh, lake, river, and stream species overlapping and providing for a really incredible day…if you like Odonates anyway.  Just as an FYI, the scenery and other wildlife is not bad either.

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