Pictorial_Highlights

PICTORIAL HIGHLIGHTS, WEEK OF 9/12/01-9/17/01

As mentioned below in our notes from September 13, 2001, our catch of many kinds of birds has begun to shift in composition from mostly hatching year (HY) to mostly after hatching year (AHY) individuals. In the photos below you can compare the definitive basic (i.e, adult winter) plumage of an AHY Magnolia Warbler, with its spring (definitive alternate) plumage. In basic plumage (top photo), an AHY male MAWA lacks the black mask and white supercilium present in its alternate plumage (bottom photo) and its solid black back is replaced with large black spots. Also, its wing bars are narrower and less bright white than in spring. Shared between the plumages, however, are the solid black upper tail coverts contrasting sharply with the bright yellow rump, as well as the species' distinctive broad white central tail band.

Adult male MAWA in basic (winter) plumage Adult male MAWA in alternate (spring) plumage

The photo below provides a comparison of the Gray-cheeked Thrush (left), with one of seven Swainson's Thrushes (right) banded today. Note the buffy eye ring and lores, warm brown auriculars (the feathered area covering the ears, i.e., roughly the "cheek"), and buff-tinged upper breast in the SWTH compared to the indistinct facial pattern, grayish auriculars, and whiter breast in the GCTH.

Unfortunately, our digital camera failed us today (low batteries and, apparently, insufficient power from the optional AC adapter), or we would have taken pictures of our first Winter Wren of the season. Before the batteries were drawn down too far, we had taken some pictures of our visiting ornithologist from the University of Zurich, Fränzi Nievergelt, hard at work. In the series of photos below she is measuring and photographing the wings, tail, legs, and feet of our second Ruby-crowned Kinglet of the season.

Also new for the fall were two Cape May Warblers, including the immature male pictured below .

Thursday, September 13, 2001
As the migration of many species proceeds, the proportion of immature:adult (and, also, especially in the spring, male:female) birds often changes as a consequence of differential migration timing among age-sex classes. Until recently, the majority of many of the kinds of birds that we band have been immature (hatching year, HY) birds, but we are beginning to catch increasing numbers of adult birds. Virtually all of the male Rose-breasted Grosbeaks banded before yesterday have been brownish streak-breasted HY birds; adult RBGR males banded yesterday and today, although not nearly as vivid as in their spring plumage, are nonetheless comparatively brightly plumaged (photo below)--they bite harder than HY birds, too!

Wednesday, September 12, 2001
Today we had our second highest capture rate, our highest daily total (by far) for Gray Catbirds (26 banded), and our first significant thrush fallout of the fall 2001 season (10 Swainson's Thrush and 6 Wood Thrush). There were no new species banded. Hooded Warblers continue to stage a very good fall flight at Powdermill--with 7 banded today (including the adult male pictured below) we are just 14 birds away from breaking our record fall total for this species (150 in 1995).

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