24 June 2007

The blues

Last weekend when doing some bird survey work close to home in the urban jungle, Stylurus was surprised to find several Spatterdock Darners, Rhioaeschna mutata, in a small pond adjacent to the channelized portion of the Rouge River. This is a species we first had a glance at in 2005, and which eluded our nets at a retention pond in 2006 -- the first records for the county. Believe me, we know every wet spot in our city, and they've never been at this familiar pond.

It's locally referred to as "the oxbow pond," but in fact before the channel was built the river bowed in the other direction (the real oxbow ponds can be seen in the last photo below, to the left of the sewage plant), and this pond was either a natural wooded wet spot, or dug during construction.

It looks rather bucolic in the photo above. It's half-covered with spatterdock (Nuphar polysepalum), but one end and part of one side are being heavily invaded by phragmites. It's wooded around the rest of the perimeter. There are fish there (as a busy kingfisher demonstrated) which are probably larger and more numerous than past years, as the edges have become so thickly overgrown there is little access for folks who used to sneak in and fish there. The homeless folks have even abandoned their long-standing camp there.

Below, the red arrow points to the pond.

There's nothing sadder than a river in a concrete channel, in my opinion. This is the same stretch, just downstream of the pond. Ford world headquarters is the building in the distance on the right.

We returned yesterday, and Stylurus bravely made his way a few feet out from shore in the water at the only access point in the phragmites. I bravely tried to find access at the opposite shore, bushwhacking my way through sharp hawthornes, grape and poison ivy vines, and various discarded appliances. Along the margin, I was able to voucher one of a few Sedge Sprites, Nehalennia irene, a first for the city, and perhaps an indicator that the water quality is improving. Meanwhile, Stylurus was able to get the first voucher of the darner for the county.

This is the most beautiful of our darners, I think. This individual was bit battle-worn, missing half a leg and one foot. We did not observe any females, and the fish in the pond would prohibit much successful reproductive activity. So far, this has just been a terrific year for odonates -- nearly every species in abundance and in new places. To a great extent this likely reflects past conditions (up to two years ago) that allowed for greater dispersal of adults followed by increased survivorship of eggs and larvae.

18 June 2007

We score!

In our long quest to voucher Anax longipes for Wayne County, we ended up the 2006 field season with a score of Comet Darner 4, Urban Dragon Hunters 0. Let's recap:
I was just awarded a grant to do baseline standardized odonata surveys at the DRIWR, as they will be restoring a large brownfield along the Detroit River shoreline, including opening up a creek that is currently underground, and constructing a pond. We did our first survey yesterday. About halfway through our sweaty second transect, a very large darner landed along the treeline. Both Stylurus and I were able to locate the perched insect: a big Anax, which looked like a female Common Green Darner (A. junius). We're just as prone to wishful thinking as the next person, but from our looks, neither of us could see the bullseye pattern on the forehead which would verify junius (right). Before we could contemplate how to get at this darner, it flew again.

It's hard to describe the sort of low-key desperation one feels when you know you might have just seen a really great dragonfly, one that you have to catch either to confirm its identity or voucher for a location, only to see it fly away. It might perch again right in front of you, or it might take off and go far, far way. This one did a few lazy loops, and landed in a locust sapling about three feet high, within a few yards of us. We crept forward, watching it with binoculars and looking for the bullseye. What we saw was... nothing. No bullseye = Comet Darner.

Although I carry the shorter net with the narrower mouth, I was a bit closer, directly behind her, and tend to be a little more of a patient stalker than Stylurus. My net bag has already been sewn up a few times, so ripping it on the locust thorns was a risk I was willing to take. Stylurus was ready off to the right. I swung, and made a clean catch without even tearing the net.

Extracting it from the net, we found out that indeed, we'd finally bagged our county voucher. This was a different location at the DRIWR than I'd seen Comet Darners previously. I suspect they occur here because the river acts as a corridor; there are no appropriate fishless ponds (or any other surface water) for them to breed in. But this bodes well for when ponds are built on the Refuge.

From the photo above, it's hard to get any true perspective on size, and she sure looks like a green darner (although the big, long reddish legs don't seem right for junius). We decided to snag a green darner just for comparison:

Longipes is much heavier bodied and just looks like a junius on steriods.

We resumed our survey, in which we ended up with 25 species. Sedge Sprite (Nehalennia irene) was a new species for the Refuge, for a total of 33 species since I first began doing bird work there several years ago.

We'll be doing biweekly surveys for the rest of the summer. Stay tuned.

16 June 2007

Long time, no see

I realize this is a crappy photo, but it was beyond the range of the macro lens I had on my camera at the time. It's a Four-spotted Skimmer (or chaser, as you folks across the pond say), Libellula quadrimaculata. There are only three specimens from the county, all before 1917. Now there are four.

We found it, and one or more conspecifics, in a retention pond behind a Wal-Mart in Canton, a place we'd not been before. It was nearly entirely grown in with cattails, and mostly full of Twelve-spotted Skimmers (L. pulchella), along with a few pondhawks (Erythemis simplicicollis) and dashers (Pachydiplax longipennis) and lots of teneral Sympetrum. This was actually a birding stop for us, so I was without my net. When I saw this dull, hairy ode amongst the twelve-spots, I called for Stylurus to come around my side of the pond. By that time, the four-spot was landing repeatedly on this dead stalk. I wasn't expecting much new, nor did I realize four-spots were so furry and dull. It was a really nice unexpected surprise!

There was a little two-track heading back to the small woodlot near the pond. Since we were doing breeding bird atlas work, we thought we'd poke around. Not a hundred yards in, we found a small wooded wetland, easy to get to and quite open compared to similar ones we've found in the county. Even though it's been dry, there was plenty of water, and although our feet got wet, we didn't sink into deep stinking muck to get to the water's edge.

Stylurus immediately had a female Swamp Darner (Epiaeschna heros) ovipositing on a rotten log. I won't even display the horrible shots I got of that. My next thought was that the site looked like a great place for Great Blue Skimmer (Libellula vibrans), very similar to the site where we vouchered the first state record two years ago. I hadn't had time to voice that thought when I got a call on the radio from Stylurus, who'd wandered ahead and found a male GBS. I'll also pass on the crappy photos I took of that one, sitting over the water on a twig. This is our third location for the species in the county. Stylurus also thought he may have seen a female -- so far, we've only seen males.

It's always fun to find a new spot, although predictably this property was for sale. But it had no trails through the open understory, not many invasive plant species (and lots of less-common species for here, such as sassafras and tuliptree), and only minimal dumping or teenage presence. And to find a new species for us for the county, plus two other "good" odes made it a satisfying day.