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.

No comments: