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Saturday, September 29, 2007

St. Clair Flats kayak Sharp-tailed search

One of the things I love most about kayaking is that it allows me to go birding in otherwise inaccessible places. St. Clair Flats, the world's largest freshwater delta, is a vast shallow marsh teeming with birds, yet I cannot remember the last time I heard a birder's trip report from this site. It is very difficult to get into this marsh.

Today Dave Slager and I decided to kayak into the depths of the flats to search its varied wetland habitats for Nelson's Sharp-tailed Sparrow. My hope was that we could follow in the footsteps of Alan Wormington who found 16 Nelson's Sharp-tailed Sparrows at Hillman Marsh Ontario (~30 miles due south of St Clair Flats) on 8 October 1995. He did this by putting on hip waders and walking through thick sedgy marsh with 2 to 10 inches of standing water. Of all the habitats we've searched to date, none has had the standing water component. So, we figured, geographically and in terms of habitat (the flats has much standing water), St. Clair Flats may offer one of Michigan's best chances for this species during fall migration.

We arrived at dawn to some fog and many fisherman putting in boats. First light revealed extensive bulrush marsh with several inches of standing water below it, and many navigable (by kayak) channels through the marsh:

We quickly realized that although the habitat very much resembled the Spartina grass beaches on which this species winters, that it would be very difficult to see the species from the boat. So, we put on waders and began hiking through the marsh to flush sparrows, rails, and whatever else was present. Swamp Sparrows and Marsh Wrens were very numerous, but surprisingly Song Sparrow was absent except at the boat dock. About halfway through the day, we found what was almost certainly a Le Conte's Sparrow, but as we were about to get a good perched view of it a Coast Guard helicopter came by and scared it away. Many of the patches of marsh were accentuated by Phragmites or Cattail, and even willow and other upland herbs. In these areas, there was a fair amount of bulrush/sedge marsh which lacked standing water, such as these two spots: Marsh Wren nests were abundant:
Shorebirds were present including Black-bellied Plover, Pectoral Sandpiper, Wilson's Snipe, and Greater Yellowlegs. Ducks included Mallard, Black Duck, Blue-winged and Green-winged Teal, and Lesser Scaup. But the surprise waterbird of the day was this incredibly confiding juvenile Red-necked Grebe! It literally allowed us to approach to within 10 feet, the closest either of us have ever been to the species.This map shows the location of our route, the probable Le Conte's Sparrow, and the Red-necked Grebe. This bird IS chasable without leaving land if it stays where we had it: at the very end of Decker's Landing at the end of Anchor Bay Dr, where the boats heading from Decker's into the main channel first hit the channel.
So, although we failed to find a Nelson's Sharp-tailed Sparrow, we only covered an extremely small portion of the available habitat. Compared to Hillman Marsh, Ont. the habitat is very dispersed and abundant, whereas Hillman is entirely comprised within a 1 X 1.5 mile patch. This may mean that birds are more widely dispersed at the flats. We also are continuing to hone our search image for this species, which may or may not prefer the flooded portions of the marsh. Lastly, sparrows were not particularly abundant today, and the few flocks we found were dispersed and seemed to contain mainly resident individuals. Perhaps in another week there will be more migrants in the area. I was thinking of trying again on Sat. 7 Oct, but that is opening day of duck season, so that may not happen! I wonder if a reluctance of birders to hit the proper wetlands during duck season may in part explain the paucity of Michigan reports of this species...

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