From south-bay-birds-bounces+south-bay-birds-archive=[[email protected]] Wed Aug 11 08:41:42 2004 Received: from www.plaidworks.com (localhost [127.0.0.1]) by plaidworks.com (8.12.9/8.12.9) with ESMTP id i7BFcpOQ012056 for <[[email protected]]>; Wed, 11 Aug 2004 08:38:51 -0700 (PDT) Received: from smtp3.Stanford.EDU (smtp3.stanford.edu [171.67.16.138]) by plaidworks.com (8.12.9/8.12.9) with ESMTP id i7BFcCMR012012 for <[[email protected]]>; Wed, 11 Aug 2004 08:38:12 -0700 (PDT) Received: from lawmail1.stanford.edu (lawmail1.Stanford.EDU [171.64.212.80]) by smtp3.Stanford.EDU (8.12.11/8.12.11) with ESMTP id i7BFcBpm029991 for <[[email protected]]>; Wed, 11 Aug 2004 08:38:12 -0700 To: [[email protected]] X-Mailer: Lotus Notes Release 6.0 September 26, 2002 Message-ID: <[[email protected]]> From: "Tom Grey" <[[email protected]]> Date: Wed, 11 Aug 2004 08:38:10 -0700 X-MIMETrack: Serialize by Router on lawmail1/stanford(Release 5.0.12 |February 13, 2003) at 08/11/2004 08:38:11 AM MIME-Version: 1.0 Content-type: text/plain; charset=us-ascii Subject: [SBB] update: visual i.d. of breeding plumage dowitchers X-BeenThere: [[email protected]] X-Mailman-Version: 2.1.5b1 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]] Two of the best local birders emailed me offline about the six pix I posted of dowitchers taken at the CCFS shorebird pond last Sunday. Both suggested that all six are probably Long-billed, since as one put it, "none of the birds in your pictures have solid white bellies and crissums." Both emphasize the uncertainty of visual i.d. of dowitchers. One describes this as "the really ugly zone" and says he tends to stick with call i.d. even for breeding birds. The other said "current criteria are tenuous," "spots and bars are very interesting but I'm not convinced," and "in the last month, as birds are molting, I've given up entirely" on visual i.d. of dowitchers. Humility is clearly the watchword here. Sibley is a bit misleading here, as he writes: "Breeding adult identified by breast pattern, juvenile by tertial pattern." This implies the two separations are about equally easy. But from reading more detailed treatments -- such as in Paulson, Claudia Wilds' chapter in Kaufman's Advanced Birding, and Hayman/Marchant/Prater, it seems that the juvenile i.d. by tertial pattern is pretty straightforward, whereas the breast pattern (spotted sides in SB vs. barred sides in LB) is much less so. (By the way, Al Jaramillo has a couple of much-cited articles on i.d. of these species, but I don't have access to them.) Anyway, here again is the link to the page with my six pictures taken last Sunday at the shorebird pond. My notes are left unchanged. I've added a seventh picture that I took last spring at Palo Alto Baylands. It shows what I think may be pretty typical spring alternate Long-billed plumage -- dark red all the way on the underparts, heavy spotting on the foreneck, and barring on the side of the breast (where SB would allegedly have spotting). Note that the neck and breast markings are much heavier in the spring bird than in any the six pictures from last Sunday -- these tend to disappear with wear, and some say differentially more so in LB than in SB. But I didn't hear this bird call, to the humility caveat applies. http://www.geocities.com/tgrey41/Pages/LongbilledDowitcherp.html Tom Grey _______________________________________________ Do not post admin requests to the list. They will be ignored. south-bay-birds mailing list ([[email protected]]) Help/Unsubscribe/Update your Subscription: http://www.plaidworks.com/mailman/options/south-bay-birds/south-bay-birds-archive%40plaidworks.com This email sent to [[email protected]]