Saturday, June 26, 2010

Roseate Tern, Shorebirds, Yellow-crowned, Rails; Installment 4 of "Where are They Now"

Vince Elia was out again this morning, finding a Roseate Tern on the beach with 30 Black Skimmers at the South Cape May Meadows/TNC Cape May Migratory Bird Refuge. A Lesser Black-backed Gull was also there. In the impoundments a White-rumped Sandpiper fed with 8 Least Sandpipers, and 3 Glossy Ibis and 4 Snowy Egrets headed south over the bay. A Willet chick continues as well.

While kayaking this morning I was surprised to have a Yellow-crowned Night-heron flush from the marsh just north of Norbury's Landing, along Delaware Bay north of Villas, where I seldom see them, though Black-crowneds are common there. The marsh, part of Cape May NWR, is loaded with Fiddler Crabs this summer, more than usual, a favorite prey item for Yellow-crowneds. There are about 80 bazillion Clapper Rails in that marsh (well, at least 20), another fiddler eater, and I was treated to an array of vocalizations, including some I would have had no idea about were I not so surrounded by Clappers. One near constant sound from the rails this morning was a single, emphatic, low burrr or purrr, - lower your voice and growl a bit as you say it, that'll give you the idea. This one I've heard before, often enough to make me wonder why it's not on any of the popular cd's. Some other rail calls today would give one pause. Best to think a moment before cavalierly naming sounds in the night, or from a bird unseen in a marsh, when there are just so many different vocalizations any given species can make.

Back to our continuing series on birds now north of us, and rewinding two weeks . . . Michael, ahead on the trail alongside Moose Bog near Island Pond, Vermont, turned and spoke. I told him later that by his tone of voice, you'd have thought he was asking if I had bug spray with me or something mundane, but what he calmly said was, "There is a Saw-whet Owl in juvenile plumage." And there was, a life plumage for all of us.

[A bird to "whet" one's appetite for the north woods. . .juvenile Northern Saw-whet Owl, Moose Bog, Vermont, June 13, 2010. The bird was gone about an hour later when we walked back past the spot. Click to enlarge.]

Northern Saw-whet Owl migration is as well documented for Cape May as anywhere, thanks largely to the efforts of Katy Duffy, who published a paper on it with Paul Kerlinger, former director of CMBO, in 1992. Paul also co-authored a 1993 paper centered on road-kill recoveries. From these papers and observations since (e.g. during the massive saw-whet invasion of 1995-1996) we can say the species migrates through Cape May from mid-October through mid-late November, especially on nights after cold fronts when the air is cool, skies are clear and the winds are light and from the north. Try for them at night during these conditions, or watch for silouettes in the very first glimmer of dawn. Saw-whets winter on the peninsula, in some numbers during invasion years (a tale sadly told by winter roadkills), but good luck finding one on its day roost with all the great habitat available. One flew in front of my truck along Jake's Landing road on January 1, 2010 (as I left after watching Short-eared Owls).

As to where they are now, a very few may not be all that far away. Saw-whets have been heard calling during breeding season in southern NJ, with nesting proven in Burlington County. But the bird is one largely of northern forests, in the east favoring conifers or mixed forest and especially fond of dense cover, e.g. rhododendron. Most of our fall birds are coming from New England, eastern Canada and the Great Lakes region.

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