From south-bay-birds-bounces+south-bay-birds-archive=[[email protected]] Mon Dec 27 15:15:05 2004 Received: from www.plaidworks.com (localhost [127.0.0.1]) by plaidworks.com (8.12.9/8.12.9) with ESMTP id iBRNCUlF013214 for <[[email protected]]>; Mon, 27 Dec 2004 15:12:31 -0800 (PST) Received: from pop-a065d19.pas.sa.earthlink.net (pop-a065d19.pas.sa.earthlink.net [207.217.121.253]) by plaidworks.com (8.12.9/8.12.9) with ESMTP id iBRNBEYK013170 for <[[email protected]]>; Mon, 27 Dec 2004 15:11:14 -0800 (PST) Received: from user-38ldv9d.dialup.mindspring.com ([209.86.253.45]) by pop-a065d19.pas.sa.earthlink.net with esmtp (Exim 3.33 #1) id 1Cj419-0004mr-00 for [[email protected]]; Mon, 27 Dec 2004 15:11:12 -0800 Mime-Version: 1.0 (Apple Message framework v619) In-Reply-To: <[[email protected]]> References: <[[email protected]]> Message-Id: <[[email protected]]> From: Les Chibana <[[email protected]]> Subject: Re: [SBB] Osprey gender identification Date: Mon, 27 Dec 2004 15:11:08 -0800 To: South Bay Birders <[[email protected]]> X-Mailer: Apple Mail (2.619) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Content-Transfer-Encoding: 7bit X-Content-Filtered-By: Mailman/MimeDel 2.1.5b1 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]] Vivek, The first reference where I had seen the necklace feature specifically called into question was in the Wheeler and Clark 1995 book, "Photographic Guide to North American Raptors". It said that the necklace feature is variable between male and female and there is overlap for both sexes. The prior guide by the two authors, "Hawks" 1987, said that both sexes are nearly identical except for size. Wheeler's recent "Raptors of Western North America", 2003, restates with "Sexes of both ages [adult and juvenile grouping] are somewhat dimorphic in the amount of breast markings, but there is overlap." He goes on to say that birds from the northern latitudes tend to have more extensive markings on the head and breast than those from the south. Otherwise, these guides note that females are "somewhat" larger but they don't show comparable measurements between the sexes. There are apparently no plumage differences. Les --- Les Chibana BirdNUTZ(tm) - Ornigasmic Birding Palo Alto Baylands Birding Classes em <[[email protected]]> web ph 650-949-4335 fx 650-949-4137 snailmail: SR2 Box 335, La Honda CA 94020 On Dec 27, 2004, at 1:35 PM, Tiwari, Vivek wrote: > The reason for this note is a question on determining the gender for > an Osprey. > The Nat Geo guide talks about the bib on the neck as indicative of a > female bird. > Sibley does not make that distinction. > > Further the following article from Hawk Watch International seems to > suggest that gender can't safely be id'ed in the field > http://www.hawkwatch.org/RaptorWatch/Fall%202001/ > Pitfalls%20in%20Osprey% > 20Identification.htm especially based on the bib. > > Are there other gender id. points to use other than the bib? > > Thanks, > Vivek Tiwari _______________________________________________ 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]]