From south-bay-birds-bounces+south-bay-birds-archive=[[email protected]] Mon Sep 22 11:42:21 2003 Received: from www.plaidworks.com (localhost [127.0.0.1]) by plaidworks.com (8.12.9/8.12.9) with ESMTP id h8MId3ID028352 for <[[email protected]]>; Mon, 22 Sep 2003 11:39:04 -0700 (PDT) Received: from rtjones.nas.nasa.gov (rtjones.nas.nasa.gov [129.99.19.30]) by plaidworks.com (8.12.9/8.12.9) with ESMTP id h8MIcNZP028315 for <[[email protected]]>; Mon, 22 Sep 2003 11:38:23 -0700 (PDT) Received: from rtjones.nas.nasa.gov (localhost [127.0.0.1]) by rtjones.nas.nasa.gov (SGI-8.12.5/8.12.5/NAS-6n) with ESMTP id h8MIcMhv038949 for <[[email protected]]>; Mon, 22 Sep 2003 11:38:22 -0700 (PDT) Received: (from mrogers@localhost) by rtjones.nas.nasa.gov (SGI-8.12.5/8.12.5/Submit) id h8MIcMWA038855 for [[email protected]]; Mon, 22 Sep 2003 11:38:22 -0700 (PDT) Date: Mon, 22 Sep 2003 11:38:22 -0700 (PDT) From: "Dr. Michael M. Rogers" <[[email protected]]> Message-Id: <[[email protected]]> To: [[email protected]] Subject: [SBB] Bank Swallow, Golden-Plover in Alviso X-BeenThere: [[email protected]] X-Mailman-Version: 2.1.2+ Precedence: list List-Id: South Bay Birding List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: south-bay-birds-bounces+south-bay-birds-archive=[[email protected]] Errors-To: south-bay-birds-bounces+south-bay-birds-archive=[[email protected]] All, I made a quick trip out to Alviso late yesterday morning 9/21/03, hoping to refind the recent good birds seen there. A huge swallow flock had gathered near the old cannery building near the Alviso Marina, with 640 BARN SWALLOWS forming the vast majority of the flock. There were also, however, 8 to 10 VIOLET-GREEN SWALLOWS, 3 to 4 CLIFF SWALLOWS (all juveniles), and a juvenile BANK SWALLOW. The BANK SWALLOW spent its time roosting on the north-facing black roof just south of the cannery building (on the opposite side of the driveway), a spot favored by many of the CLIFF and VIOLET-GREEN SWALLOWS as well. It was easily aged by the extensive pale edgings to the coverts and tertials. Tom Grey told me that the American Golden-Plover was still around, so I quickly headed out along the railroad tracks with high hopes. Unfortunately, there was no golden-plover visible when I got out there. Undaunted I continued to check further reaches of New Chicago Marsh by heading back towards the Alviso Marina along the railroad tracks, finding the adult AMERICAN GOLDEN-PLOVER not that far off the tracks in the marsh. Having read Al Jaramillo's post, the identification of this bird should be discussed further. Al thought that perhaps the long-winged appearance of this bird might be "partially an illusion". It is not. The bird is long-winged, with the wing tip extending well past the tail tip by a distance that is fairly typical for AMERICAN GOLDEN-PLOVER in my experience. The bird is definitely not in its first fall, as evidenced by the presence of several black spots on the underparts that do not show well in Tom's photos. Al noted that "the extensive amount of golden on the upperparts pretty well eliminates American Golden Plover which is much more grey-brown above as a non-breeding (basic plumage) adult". This may be true for a basic individual, but this species molts late (as Al also noted) and typically retains much alternate plumage during migration. In fact it seems to me that the bird is still mostly in alternate plumage. Many adult females (especially one-year old birds) may not acquire much more black than this individual, suggesting that the underparts may not have changed all that much as a result of molt. All this being said, some golden-plovers cannot be identified even in the hand, so caution, particularly for adults in transitional plumages, is warranted. In addition to the wingtip extension past the tail it is important to note the primary extension past the tertials. In general, this too appeared quite long. However, I had some difficulty assessing this feature, as it appears that there is some molt going on in this area, as Bill noted when he originally found the bird. On the right hand side of the bird I noted a surprisingly long pale-edged feather extending well out over the primaries. This was apparently the longest tertial, although I was surprised that it was not notched like the others (perhaps a new basic feather?). Additionally, so much of this feather was exposed that I believe other feathers (tertials?) that would normally cover its base had been dropped. The left side of the bird did not show this longest tertial and therefore showed longer primary extension. This is exactly the kind of situation where assessing the true primary extension can be problematic. Fortunately, Tom's photos capture these features as well. Looking at http://www.geocities.com/tgrey41/GoldenPlover4.jpg (right side of the bird) you can see the longest tertial quite well. From the photo it appears that there is actually a hint of "notching", with the yellowish edging being broader and brighter at regularly spaced intervals along the base of the feather. Looking at the left side of the bird http://www.geocities.com/tgrey41/GoldenPlover5.jpg, a correspondingly patterned and long tertial is not apparent. Because of this, many primary tips are exposed (six?, with the outermost two being nearly the same length). One must use the other side of the bird to judge the primary extension past the tertials, which I had some difficulty assessing (it seemed more like an ambivalent 3 or 4 primary tips). However, Mike Mammoser had excellent looks at this right side and always saw at least four primaries past the tertials, again indicating an AMERICAN GOLDEN-PLOVER. There are those who believe that most adult American Golden-Plovers seen in California are misidentified Pacific Golden-Plovers. I doubt that they would be convinced of the ID of this bird based on Tom's photos, but the wing tip structure of this bird does seem consistent with that species to me. An adult PEREGRINE FALCON flew off towards the Marina with prey. A nice smattering of newly arrived wintering birds included my first-for-the-fall SAY'S PHOEBE, YELLOW-RUMPED WARBLER (flyover), and AMERICAN PIPIT. Mike Rogers _______________________________________________ Do not post admin requests to the list. 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