Tag: Odonata

More Odonates

In among the errands I had to run today, I managed to find time around noon to take a walk at the Concord unit of Great Meadows National Wildlife Refuge. It was hot and humid with a light breeze (8-11 mph), enough wind to keep the temperature bearable. The breeze and the time of day meant the birds were keeping under cover, so I spent half an hour looking at damselflies and dragonflies (Odonates).

I managed to get close enough to photograph three species reasonably clearly. As I tried to identify those species from photographs, I got introduced to the chalenges of Odonata identification. One species was easy to identify:

The above photograph shows a Common Whitetail (Libellula [Plathemis] lydia), in the Skimmer family (Libellulidae). This was a straightforward identification. According to Blair Nikula et al., A Field Guide to the Dragonflies and Damselflies of Massachusetts, “identification of most species [of Skimmers] is possible in the field based on a combination of body, eye, and wing color and pattern.” And this is a particularly distinctive species.

The next taxon, however, was more difficult. Based on the photo below, I’m willing to place this individual in the genus Enallagma, the Bluets. But I’m not willing to make any determination as to species: “The bluets (Enallagma) … are very difficult to identify without examining the male terminal appendages under a hand lens or loupe” (Nikula et al., p. 31). That would mean capturing the insect with a net, holding it the hand, and examining it; I don’t have an insect net, and, not being particularly coordinated, I’d worry about damaging the insect while trying to examine it.

The next taxon, shown below, was even more difficult. All I’m willing to say is that this individual is in the family Corduliidae, or Emeralds. To take the identification to the level of species, once again I would have needed to capture the insect. According to Nikula et al., “although genera can often be recognized in the field with experience, identification as to species is very difficult, typically requiring in-hand examination of subtle body markings, male terminal appendages, or the female subgenital plate.” I’ll be happy if I ever get good enough to identify the Emeralds to the level of genus.

At this point, I don’t feel the need to make specific identifications of every individual; it’s enough for me to appreciate the unexpected diversity of the Odonates.

Published a day later than the date on the post, due to travel.

Odonates

Just before noon, Abby and I took a walk along the recently-opened Bruce Freeman Rail Trail that runs from Chelmsford, Mass., through Acton. The part of the trail we walked, around the Route 2A crossing, passes through several wetlands, with a few small areas of open water and some nice cattail stands. I was mostly looking (and listening) for birds, and even in the heat of the day there was a nice variety of birds, from Red-winged Blackbirds, Common Yellowthroats, and other swamp-loving birds to forest-nesters like American Robins and Chipping Sparrows. Abby was most interested in the Red Squirrel population. However, it was hot enough that there weren’t enough birds or Red Squirrels to keep us occupied, and we both began noticing insects in the order Odonata (dragonflies and damselflies) along the trail; I do not know much about about Odonates, but it sure looked like there were quite a few different species flying around us.

I am intimidated by the challenges of identifying Odonates; I find them hard to track in my binoculars, and I find it difficult to observe the level of detail required for identification down to the species level (sometimes you have to be able to see the shape of the male sex organs to get a definite identification). But my new camera has a really good zoom lens, and I find it easier to try to make an identification from a photo. I managed to get one reasonably good photo of an Odonate. A tentative identification might place this insect in the Aeshnidae family, or Darners, according to A Field Guide to the Dragonflies and Damselflies of Massachusetts by Blair Nikula et al. (Westborough, Mass.: Massachusetts Division of Fisheries and Wildlife, 2003), p. 69. Unfortunately, the photo does not show how the insect’s eyes come together, a key identification point for this family.

 

Later the same day:

After taking care of some business we had to deal with, Abby and I went for a short walk at Great Meadows National Wildlife Refuge, one of our father’s favorite places to go for a walk. I did a little birding, until Abby and I both became fascinated by the dragonflies and damselflies flying around us. I was able to get pretty good photos of a few of these odonates.

The photo above shows, I believe, a young female Eastern Forktail (Ischnura verticalis); I’m fairly certain about the genus, less certain about the species. I’m basing my tentative identification on the species account in Nikula et al., p. 56. And I’m somewhat more confident of this identification because on p. 30, Nikula et al. state that the Eastern Forktail “is probably the most widespread and common odonate in Massachusetts.”

And above is a photo is of an older female of, I think, the same species; older females of this species, according to Nikula et al., “become extensively pruinose blue-gray.”

The photo above shows one of the many Blue Dashers (Pachydiplax longipennis) patrolling the marshes and the edge of the river in Great Meadows. I’m fairly certain of this identification, and this is quite a common dragonfly in Massachusetts.

We also saw a couple of Monarch Butterflies, and an unidentified sulphur butterfly. I didn’t find many birds today, but the spectacular Odonata and Lepidoptera we saw more than made up for the lack of birds.

Black Wolf, Wis.

I spent an hour in the afternoon on a dock poking out into the muddy waters of Lake Winnebago. I was mostly looking at birds, but I also watched the airplanes flying by. The Experimental Aircraft Association in Oshkosh is hosting AirVenture, a week of air shows, mass arrivals, experimental aircraft, antique aircraft — it’s one of the largest air shows anywhere. The EAA Seaplane Base is just a couple of miles up the lake from us, and while I sat on the dock a dozen or more small seaplanes flew past the little cove where I sat. Then I heard a much deeper, louder sound, and through the trees a gigantic Martin Mars, a four-engine seaplane with a 200 foot wingspan, appeared overhead, circled slowly around and settled down towards the water.

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The huge red and white plane disappeared behind some trees. I watched through the binoculars, and when it reappeared I could see the huge bow wave sent up by the Martin Mars.

A few minutes later, I looked down and saw a different kind of seaplane. A small insect in the order Odonata flew down and landed on the surface of the water. Because it spread its wings out on either side of it, I’m going to say it was a dragonfly, suborder Anisoptera. But that’s as far as I can go; I can’t even say what family of dragonflies this individual belonged to. But that’s beside the point; what interested me was that this insect was able to land on the surface of the water, apparently supported just by surface tension, and then take off again. What an amazing insect.

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When an orange-and-white butterfly landed on a lily pad, I have to admit that I felt relieved, because I knew I could identify the species. It was a Bronze Copper, a common butterfly in Wisconsin at this time of year. I’m not sure why I feel the need to be so specific with identification; I’d like to think it’s because it helps me better understand the evolutionary connections between organisms.