22 June 2008

Cobra Clubtail: Unofficial county record

Last week, Stylurus asked what might we see on our next weekly survey of the Detroit River IWR. Our first new species for the Refuge was sort of pedestrian -- an Ebony Jewelwing (Calopteryx maculata). After that, things were a little dull. We split up to each do a transect, and were nearing the end of our routes when I got a call on the radio. Stylurus told me he had a different sort of clubtail.

I looked over, and he was only 30 yards or so from me, standing about 20 yards from the Detroit River (which is just on the other side of the line of cottonwoods in the shot below). This spot is tall grass interspersed with clumps of Eupatorium altissimum (tall boneset) and encroaching dogwood shrubs (Cornus racemosa or drummondii) which grow thickly in front of the cottonwoods.

He called me over, telling me he thought he had a Cobra Clubtail (Gomphus vastus). This seemed highly unlikely, but whatever it was had to be interesting. Normally, we'd just go ahead and catch something like this. Gomphids can be hard to ID unless in hand, and almost any clubtail would be a new Refuge record. However, as he soon pointed out to me, it was perched in amongst a clump of dogwood. There was no chance for a swing. He had taken a couple of photos, since it had been sitting there for several minutes, and I also got the single shot below.

Indeed, a Cobra Clubtail! It flew, but not far, and we both went after it. Instead of cooperatively flying only a few yards and sitting in a low spot, it completely disappeared within a minute. We searched the whole area for nearly an hour, but never saw it again.

I'm glad we got diagnostic photos of this fresh female, but a voucher would have been made the record official when deposited in the collection at the University of Michigan Museum of Zoology, and made this rather unbelievable record more real for us! I suspect this species is probably not quite as uncommon as the sparse specimen record for the state reflects. There are only ten state specimens, and none from the southern half of the Lower Peninsula since 1917. And no records from Wayne County.

I have a feeling I know what we'll be doing next weekend.

15 June 2008

Painted dragons!

Nannothemis and I performed another dragonfly survey at the Humbug Marsh unit of the Detroit International Wildlife Refuge near Trenton, Michigan.

With summer coming along, we knew we'd find greater variety. Soon after arriving I heard over the radio that Nannothemis was stalking a Painted Skimmer (Libellula semifasciata). This would be a new ode for me in the county, as my wife had found the first county record on June 16, 2005. I soon found her standing below a tall patch of phragmites with the skimmer perched at the top.

Here's a picture of this 2nd county record at a lower level.

Continuing the survey, we found many of the expected species such as this female Twelve-spotted Skimmer (Libellula pulchella):

Female Eastern Pondhawk (Erythemis simplicicollis) -- note the urban/industrial sewer lid habitat:

Upon returning to the western end of the Chrysler property, I found a second Painted Skimmer (Libellula semifasciata) at the same wet spot that hosted the Band-winged Dragonlets (Erythrodiplax umbrata) last year. Here's the third county record .

and another look at the wet spot (as of last fall):

What will we find next week?

12 June 2008

Early ode surveys

Last year we weren't able to start our odonata surveys to find the early species that are present at Humbug Marsh of the Detroit International Wildlife Refuge near Trenton, Michigan. This last weekend's survey on June 8th added one new species Dot-tailed Whiteface (Leucorrhinia intacta) for the refuge. More surprisingly, we had a new early date for Michigan of Spot-winged Glider (Pantala hymenaea) with several individuals being recorded. The photo below is from a previous season.

On the previous day, we ran a bird survey in the natural area at the University of Michigan-Dearborn, but enjoyed seeing many dragonflies. Several species were freshly emerged:

Slender Spreadwing (Lestes rectangularis)

Blue Dasher (Pachydiplax longipennis)

Twelve-spotted Skimmer (Libellula pulchella)

For one species, we found the remains of its emergence from the water. This exuvia of a Common Green Darner (Anax junius) was found on a cattail.

Another species, Eastern Forktail (Ischnura verticalis) was working on the next generation.

Finally, we saw an ovipositing Unicorn Clubtail (Arigomphus villosipes). She's facing us in the upper center of the photo above the submerged log.

08 June 2008

Urban European Dragon Hunter

Hallo from Stylurus.

I was fortunate to make a business trip to Weilimdorf, Germany at the end of last month. This is basically a suburb of Stuttgart.

Upon arriving on the trans-Atlantic flight I had jetlag and decided the best thing to stay awake would be a walk up to Gruener Heiner (a large hill made of WWII debris with a wind turbine at the top).

While walking to the hill, I found a little man-made pond in front of a home/office furniture store. The photo below is from the top of Gruener Heiner and the store with the pond is located near the left center area of the photo and is the grayish colored building beyond the freshly-cut hayfield.

Initially I didn't think about insects at this pond, but my foggy mind soon realized there were dragonflies buzzing about the edges.

There were 3 or 4 Four-spotted Skimmers (Libellula quadrimaculata), aka Four-spotted Chaser in Europe. These were the only Anisoptera observed here.

I ended up being challenged by the Zygoptera since there were many individuals of various sexes, ages, and species. Here are three of the species:

Large Red Damselfly (British) or Fruhe Adonislibelle (German) - (Pyrrhosoma nymphula)

Blue-tailed Damselfly (Ischnura elegans) - a species of forktail

immature female Blue-tailed Damselfly (Ischnura elegans)

infuscans form of Blue-tailed Damselfly (Ischnura elegans)

Azure Damselfly (Coenagrion puella). The black u-shaped pattern on S2 is diagnostic for this species.

Up on Gruener Heiner, I did find another species of Zygoptera but they were too wary to allow a photo (or maybe my jetlagged reflexes were too slow?). It was a jewelwing or demoiselle (Calopterex sp., maybe Calopteryx virgo?). I didn't even note fieldmarks since I was then distracted by a singing Blackcap (the warbler, not the fruit).

Hopefully I can take Nannothemis overseas in the future for some ode hunting. Thanks to her for ID'ing the species from home while I was in business meetings the next day.

For now, Auf Wiedersehen.