Re: The Not-A-Glaucous Gull (possible Kumlien's - pictures)


Noah Arthur
 

Alvaro, Jerry, and everyone else interested in this mind-numbing gull debate:  
 
I agree that kumlieni is genetically intermediate between thayeri and glaucoides. BUT I don't think that makes it not be a valid taxon. Looking at the range maps in Howell & Dunn's book, I can see only a tiny area of contact between kumlieni and thayeri, none between kumlieni and glaucoides, and none between glaucoides and thayeri. So, if kumlieni is in fact a hybrid populiation, it would have to have arisen sometime in the past, at a time when the ranges of glaucoides and thayeri overlapped. At this point in time, glaucoides and thayeri don't overlap, and kumlieni is a more or less isolated intermediate population. The big question is: When does such a population stop being a hybrid swarm and start being a taxon?
 
As an example of hybrid speciation, the recently described Appalachian Tiger Swallowtail -- an eastern relative of our Western Tiger Swallowtail (the big yellow city swallowtail) -- is considered a hybrid species that arose from contact between Eastern and Canadian Tigers. So if this kind of thing happens with butterflies, why not with gulls? Kumlieni has little or no range overlap with its relatives, and is more or less phenotypically distinct (a lot more gray-winged birds than white or black within its range), so why isn't it a hybrid species (or subspecies)?
 
The situation with Western and Glaucous-winged seems very different, in my opinion. There is no place where only hybrids breed. Even within the "blend zone", a hybrid may mate with another hybrid or a pure bird of either species. That is what I would call a bona fide hybrid swarm. But if a hybrid population is isolated so that hybrid birds only breed with each other -- never with pure birds of either species -- as is the case with kumlieni -- might that population qualify as a valid taxon?
 
Just my thoughts on this very complex issue...
 
Noah


On Wednesday, January 8, 2014 1:12 PM, Alvaro Jaramillo wrote:
Noah
 
There is no way to know, you have to decide in the same way you decide that a bird is a Western and not a Western x Glaucous-winged hybrid. It is a question of degree, as based on all available evidence Kumlien’s is a population of mixed genes (Thayer’s x glaucoides).
 
This is what I wrote to Stephanie:
 
It is all about definitions. The way I view it, based on the work of various biologist, mainly Canadians. There is a large hybrid swarm in the northern and eastern Arctic between Thayer’s in the north/west and glaucoides Iceland in the south/east. These birds are Kumlien’s, I do not think that kumlieni is a taxon, but a hybrid swarm. Therefore there is nothing such as kumlien’s x Thayer’s as that would also be a kumlien’s. Now my view does not conform to the current taxonomy of the AOU, so I have to bend a little in trying to identify a bird, as sometimes we are identifying things that are really not well defined (Kumlien’s). One thing that has never been defined, and has never been talked about seriously by scientists is the concept of Kumlien’s x Thayer’s, the assumption is that these are Kumlien’s, so you either accept as a Kumlien’s or as Thayer’s, there is nothing in the middle… that is Kumlien’s.
 
 
Alvaro Jaramillo
alvaro@...
www.alvarosadventures.com
 
From: EBB_Sightings@... [mailto:EBB_Sightings@...] On Behalf Of Noah Arthur
Sent: Wednesday, January 08, 2014 1:05 PM
To: EBB_Sightings@...
Subject: Re: Fwd: [EBB_Sightings] RE: The Not-A-Glaucous Gull (possible Kumlien's - pictures)
 
 
Thanks everyone for your continued interest in this bird! Jerry, thanks for refinding the bird and taking such great photos!
 
Stephanie, could you forward this email to Alvaro? I don't think I have his email address.
 
 
Alvaro:  
 
I agree the bill is big for Kumlien's, but not out of the range of variation (if you look at pictures from the East, you'll see some really big-billed ones, even some with strong gonydeal angles, but with plumage much too pale for Thayer's).
 
And I agree that it's possible that some Thayer's could have primaries this pale, but my question is: How do we know for sure that such birds aren't Kumlien's Gulls? If Kumlien's Gulls in the east often have primaries this color, and can have a bill as big as this, then how can we be sure that this bird (and others like it) aren't Kumlien's? Is there any proof that such birds are in fact Thayer's?
 
Noah
 
 
 
On Wednesday, January 8, 2014 12:35 PM, Jerry Ting <jtnikon@...> wrote:
Here is the reason why I don't think it's a pure Thayer's:
 
 
The dark web on the outer primary should be equally distinct from P6-P10 for the Thayer's which is not the case on this bird.
 
I do think the bill size is problematic though. 
 
On Wednesday, January 8, 2014 12:13 PM, Jerry Ting <jtnikon@...> wrote:
Stephanie,
 
Thanks for forwarding the message.
 
The reason why I eliminate the pure Thayer's is not because of the pale/brownish primary color.  I am leaning more on the pattern (i.e. the dark webs on outer primaries).  Colors will look quite differently in different lighting situation but the pattern will remain the same.  Just my 2 cents.
 
Thank again for all your help!
 
Best,
Jerry
 
On Wednesday, January 8, 2014 11:24 AM, Stephanie Floyd <scfloyd2000@...> wrote:



Begin forwarded message:
From: "Alvaro Jaramillo" <chucao@...>
Date: January 8, 2014 at 11:22:57 AM PST
To: "'Stephanie Floyd'" <scfloyd2000@...>
Subject: RE: [EBB_Sightings] RE: The Not-A-Glaucous Gull (possible Kumlien's - pictures)
Stephanie
 
  I would call that a Thayer’s Gull, second cycle birds sometimes have very blackish primaries, other times they have very brownish ones. This is a brownish one. Structure is typical Thayer’s. I think to call a Kumlien’s in California at this age one would  need it to be very much paler on the primaries, and hopefully smaller billed than this bird.
 
Regards,
 
Alvaro
 
 
From: Stephanie Floyd [mailto:scfloyd2000@...]
Sent: Wednesday, January 08, 2014 8:25 AM
To: chucao@...
Subject: Fwd: [EBB_Sightings] RE: The Not-A-Glaucous Gull (possible Kumlien's - pictures)
 
Good morning, Alvaro - would love to hear your opinion on this gull. Thank you! Stephanie


Begin forwarded message:
From: <jtnikon@...>
Date: January 8, 2014 at 12:53:24 AM PST
To: <EBB_Sightings@...>
Subject: [EBB_Sightings] RE: The Not-A-Glaucous Gull (possible Kumlien's - pictures)
 
I went to Lake Merritt this (1/7) afternoon and re-found the possible Kumlien's around 1:30PM at the sand beach (west of the garden center, south of the gazebo).  The lighting situation is perfect - overcasting without strong contrast, which helps to bring the true colors and tonal ranges of the subject.
 
I observed this gull for about 50 minutes and was able to acquire shots from different angles.  At around 2:20 it flew to the west bank and I lose sight of it.  But around 2:45PM I re-found it at it's usual spot - on the rooftop of the boat house.  Here are 2 sets of shots of this gull:
 
Some key features of this gull are:
- Body size: smaller than the nearby Glaucous-winged, Western and Herring.
- Bill size: smaller/slender than Glaucous-winged and Western.  Resemble to Herring but shorter.
- Bill color: two-toned and not so clear cut as Glaucous but also not as smudged like Glaucous-winged.
- Head shape: more round (like Thayer's) instead of oval (like Glaucous-winged and Western).
- Back: pale gray mixed with pale brown. 
- Tail: dark brown with thin white edges.
- Greater coverts: well-defined and contrast unlike Glaucous-winged which is smudged.
- Primaries: wingtips are brown. P5-P10 have dark outer webs where the dark on P5 and P10 and very faint. 
 
So my vote is either Kumlien's OR Kumlien's/Iceland x Thayer's Hybrid.  I would very appreciate to know others opinions.
 
Later in the afternoon, I was able to find the 1st cycle Glaucous Gull on the east side of the Lakeshore Drive across the sanctuary islands.  Here is a distant shot of this big, beautiful gull:
 
Happy Birding,
 
Jerry Ting
Fremont
 
 
Yesterday I posted photos of a gull at Lake Merritt that was not a Glaucous Gull.  I saw the Glaucous Gull today - very big, very white from stem to stern despite its beige speckling.  Like many birds, no doubt about it when you see the real thing: they look just like themselves.
 
A couple of people (Jerry Ting and Noah himself) recognized yesterday's bird as the same gull that Noah Arthur photographed extensively and posted about on January 3:
 
The five great birders who commented to me offline all agreed that it's not a Glaucous Gull. Beyond that, they speculated that it might be:
1) 2nd cycle Glaucous-Winged
2) Herring x "something"
3) Herring x Glaucous  (except it's too small)
4) Herring x Glaucous-Winged (except it's too small)
5) Pale 2nd cycle Thayer's (2 votes, and I'm leaning this way, too)
6) Kumlein's Iceland Gull (despite its bill) (2 votes)
 
Jerry was going to try to find and photograph it this week.  I did not see the gull today despite looking through a hundred (mostly Ring-Billed) Gulls before I found the real Glaucous Gull.
 
 
Stephanie Floyd
Fremont
 
 
 
 


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