Phil's point is true and I don't believe I was a proponent of stating that I didn't think hybridization was a likely cause. I am just not well-read or informed at all about what really is going on with the whole Iceland-Thayer's relationship..it is a murky gene pool with no lifeguard. Julian Hough New Haven, CT 06519 www.naturescapeimages.wordpress.com
________________________________ From: Phil Jeffrey <[email protected]> To: julian hough <[email protected]> Cc: & [NYSBIRDS] <[email protected]> Sent: Thursday, January 16, 2014 3:30 PM Subject: Re: [nysbirds-l] Iceland gulls To me it makes no more sense to dismiss hybridization amongst those two species as a mechanism for primary darkening than it does to invoke it. Just because it's not proven doesn't mean the alternative is true either. It would be one thing if, say, glaucoides in Iceland (the country) were darkening its primaries or Glaucous Gulls or even (American) Herring Gulls were seen to do so, but I'm not aware of any such trend. A Western birder might find the idea that two similar gull species *not* hybridizing to be alien to their experience, for example. >From my POV it makes sense to attempt to normalize intra-(sub)species >variation by looking at that spread in Iceland glaucoides populations in, say, >Iceland itself. While more or less anything can happen with gulls, I'd be a >lot less likely to find the "intrinsic variation" idea worthy of Occam's Razor >if the range of variation in the bird-oft-referred-to-as-Kumlein's >substantially exceeds that in the glaucoides subspecies. Or, more plainly put - point me to the preponderance of evidence that hybridization is *not* going on in this form of Iceland Gull (or whatever it is). Phil On Thu, Jan 16, 2014 at 12:29 PM, julian hough <[email protected]> wrote: Shai distilled down some common-sensical aspect of the complications surrounding Iceland Gulls and what our perceptions are about how solid these are as a taxon. As an exiled Brit, I grew up on nominate glaucoides Iceland Gull and it often involved searching through these for a vagrant kumlieni "Kumlien's" Iceland Gull. >It is more a continuing bad-habit that I refer to them as Kumlien's Gull here >since, as Shai points out, there really isn't that much of a need for >separating them to sub-species level in the US, as perhaps there is in Europe >where kumlieni shows up more regularly. > > >Interestingly, adult iceland Gulls were scarce here in New England compared to >the numbers of first-cycle birds so it was always cool to see an adult. The >ones I have seen here in CT have all been mid-grey – to pale grey pigmented >and black-primaried individuals seem rather uncommon at this latitude. Not >sure that as quantitative evidence it amounts to anything from a scientific >aspect but I wonder what drives the range of pigmentation in these >birds…hormones, geography, actual hybridization? > > >There seems to be a lot of talk – confusion – is perhaps more apt about what >these birds are based on perpetuated myths about "hybrid swarms "of kumlieni >or interbreeding populations of kumlieni x thayeri etc and as Shai points out >it may not benefit us, in lieu of quantitative and qualitative scientific >study, to continue thinking that black-primaries Iceland Gulls here in the US >have "x" amounts of thayeri genes flowing through them and more >whiter-primaried birds have perhaps a more glaucoides influence. > > >As for separating adults from nominate glaucoides Iceland Gulls from Northern >Europe, certain birds in Newfoundland seem to check the right boxes so with >care the odd bird might be identifiable by sharp observers. > > >Intrestingly, the long-calls of these white-winged gulls was recently studied >and written up by Belgium birder Peter Adriaens here: >http://birdingfrontiers.com/2014/01/09/calls-of-thayers-kumliens-and-iceland-gulls/ > > >Good birding, > > >Julian > >Julian Hough >New Haven, CT 06519 >www.naturescapeimages.wordpress.com > > > > >-- >NYSbirds-L List Info: >Welcome and Basics >Rules and Information >Subscribe, Configuration and Leave >Archives: >The Mail Archive >Surfbirds >BirdingOnThe.Net >Please submit your observations to eBird! >-- -- "If you lie to the compiler, it will get its revenge" - Henry Spencer -- NYSbirds-L List Info: http://www.NortheastBirding.com/NYSbirdsWELCOME http://www.NortheastBirding.com/NYSbirdsRULES http://www.NortheastBirding.com/NYSbirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/[email protected]/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/NYSBirds-L 3) http://birdingonthe.net/mailinglists/NYSB.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
