From south-bay-birds-bounces+south-bay-birds-archive=[[email protected]] Fri Nov 15 13:29:18 2002 Received: from www.plaidworks.com (localhost [127.0.0.1]) by plaidworks.com (8.12.2/8.12.2) with ESMTP id gAFLRF7r018663 for <[[email protected]]>; Fri, 15 Nov 2002 13:27:15 -0800 (PST) Received: from merlin.arc.nasa.gov (merlin.arc.nasa.gov [128.102.219.21]) by plaidworks.com (8.12.2/8.12.2) with ESMTP id gAFLQhke018623 for <[[email protected]]>; Fri, 15 Nov 2002 13:26:43 -0800 (PST) Received: from merlin.ARC.NASA.GOV by merlin.ARC.NASA.GOV (PMDF V6.1 #46498) id <[[email protected]]> for [[email protected]]; Fri, 15 Nov 2002 13:26:40 -0800 (PST) Date: Fri, 15 Nov 2002 13:26:40 -0800 (PST) From: [[email protected]] To: [[email protected]] Message-id: <[[email protected]]> MIME-version: 1.0 Content-type: TEXT/PLAIN; CHARSET=us-ascii cc: [[email protected]] Subject: [SBB] Nutmeg Mannikins and Breeding Bird Atlases X-BeenThere: [[email protected]] X-Mailman-Version: 2.1b4+ Precedence: list List-Unsubscribe: , List-Id: South Bay Birding 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]] Folks: Breeding bird atlases define three basic levels of breeding evidence: (1) possible breeding, (2) probable breeding, and (3) confirmed breeding. Possible breeding is generally just the presence of a bird, although it is necessary to avoid putting migrating or wintering birds in this category. Probable breeding evidence includes such things as extended singing (over a week), territorial defence, courtship behavior, and the like. Confirmed breeding includes those things that we believe positively define a breeding record. This includes things such as nest building, incubation, eggs or nestlings in a nest, and dependent young outside a nest. The world of biology is far too rich to let us get away with such simplistic definitions. For example both House and Marsh Wren males will build dummy nests to attract a female. She will then select the final nest and will add fine materials to the nest to finish it. For these species, seeing an adult carrying nest material or building a nest is not sufficient evidence to confirm breeding. Knowing this bird's biology, we downgrade the evidence to probable in this case. Recent discussions with David Suddjian about Nutmeg Mannikins along with some references to aviarists suggests that although this exotic is breeding in small numbers in the Almaden Lake area much of our evidence for nesting probably refers to other behaviors. From the very limited sources I've been able to find, it appears that this species as a matter of course builds roosting nests. If these nests are not part of courtship (a good question), then seeing mannikins carrying nest material is no more than possible evidence. Also relevant is the construction technique used by this species for roosting nests. They tend to seek out very dense shrubbery, perhaps with thorns, and then just push the nest material into the shrubbery loosely. After nest usage they can then easily reuse the material for another roosting nest at another location. A number of observers in the Almaden Lake area have commented as to the unusual times of years that this bird is building nests. If what we are seeing is only roosting nests, then this is not unusual at all. In particular, this sort of behavior would explain the very curious observation of Linda Sullivan and Peggy Don (3/2/2002) that they found 10-11 nests along Alamitos Creek, yet Ann Verdi (3/8/2002), following Linda's detailed description could find no nests six days later. It seems likely that these were temporary roosting nests that were later pulled apart and used elsewhere. So, does that mean that these birds aren't nesting locally? Not quite. There are two confirmations based on other evidence: <7/28/01 1+ nestlings; above Almaden Lake, SCL (Pat Kelly fide John Meyer); reported adults with food and nestlings heard, but not seen 3/21/02 1 ad, 4 fledglings; Almaden Lake Park, SCL (Jim Danzenbaker); female feeding four 'voracious youngsters' in reeds at SE corner of lake By the way, as best I can tell from references, the sexes are indistinguishable. The immature is different and lacks the rich colors of the adult and the shell-like or scaly breast. I don't know how long the immature plumage is held. This is a very common aviary bird and is apparently easy to breed. The presence of birds in immature plumage anywhere locally is not evidence of breeding in the wilds (of Almaden Lake). Keep your eyes out on the Almaden mannikins and see what you can figure out about their roosting nests and their actual breeding. Bill _______________________________________________ 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]]