14 July 2007

Best population of Great Blue Skimmers

Yesterday, I was doing some bird work in an undersurveyed area in Riverview, a downriver community of Wayne Co. Young Patriot's Park is a place I'd been a couple of times -- ball fields, a playground, library, basketball courts, and a woodlot at the northern end. The name stems from the period (1956-1962) when the site was a Nike missile base.

There is a decorative mowed-to-the-edge pond out front, and lots of skimmers and Pantalas flying around the open areas. I'd walked the edge of the woodlot for birds before, as well as some of the trails in it. Yesterday, I started at the north end, and soon discovered that there is a "creek" -- really a straight, shallow ditch -- running through the north end of the forested area. It's been extremely dry here, and the ditch was either dry, damp, or with perhaps three or four inches of water at its deepest. Kids had built a bridge across it where it crossed the trail, but there was plenty of naturally-fallen saplings as well as the usual discarded objects ubiquitous in urban waterways. Personally, I hopped across on a soggy car seat.

It wasn't too hard to walk close to the edge most of the way, as the woodlot clearly flooded in spring, especially on the north side of the ditch, so there wasn't as much undergrowth. The first thing I saw was a male Great Blue Skimmer lazily gliding after a conspecific, then perching in the dappled sunlight on a broken shrub arched across the water. If there is one thing about this species, it is certainly predictable in its habits.

Every few yards, in sunny spots, there was another one or two males. Standing in a patch of grape vines along the banks, two kept mixing it up and landing at my feet. Of course, I did not have my good camera, only a point-and-shoot. The fact that I finally got this nice shot (the best of any so far) and several others is an indication of how unwary and close they were. I didn't have a net either, but did try to swat one with my bird checklist.

They are not that unwary.

At one point I looked ahead, and saw a female skimmer ovipositing in the ditch with the same forward-flicking abdomen dip that I associate with Orthemis. She was very dull and in the shade, but when she finished and went up to a sunny leaf to perch, I saw it was a female Great Blue. The ditch only ran a couple of hundred yards, and without too much effort I was able to count around 15 males and at least 4 ovipositing females. These are the first females seen in the county, and the first positive evidence of a breeding population in the state.

This was just an odd and unlikely location, but it clearly floods a lot in spring, and probably stays fairly wet in less-parched summers. It will be worth a few return trips.

1 comment:

Tom Arbour said...

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