Re: Crown Beach Vireo


Joe Morlan
 

All,

I sent the additional photos by Jerry Ting and some of the additional
descriptive commentary to Matt Heindel and here is his further assessment.
The "yellow spot" is the spot near the flanks.

--------------------------------snip----------------------

"This vireo is fascinating and what I love and hate about them. First, the
yellow spot is fine for a HY Plumbeous. I have seen it in the field and in
specimens, all from core PLVI range, so there was no reason to suspect
intergradation. I do see some possible greenish tint- after staring at the
picture for too long I throw up my hands. If I saw this bird I would call
it a Plumbeous, but if those edges really are green, I do not have any
evidence to say PLVI can show this, so I would have to be talked into a sp.
I cannot see this as a pure Cassin's. First, I have never seen a Cassin's
where I have to strain to see green. Second, only the dullest CAVI can have
so little yellow and, in fact, I suspect this is outside the extreme. As
mentioned earlier, if this is a CAVI, to have that much white in the tail,
this has to be on the adult male side of CAVI, perhaps an adult female and
they are more bold, more attractive. But HY CAVI do not show this much
white. HY female CAVI typically have a pale grayish or grayish-white edge,
whereas this bird has a distinctly bold white edge to the outer rect. But,
where is the green in the upperparts? HY female are entirely green and AHY
female and HY male have nice gray head with green back. The bird in
question is gray throughout except for a yellow spot on flanks and some
light greenish tinge to the secondaries.
One thing I worry about is the potential for a flash to alter the natural
color.so perhaps someone can comment on that.
Back to your original question of are you making too much of the greenish
edges to the secondaries? My answer is I don't know. I never noted it in my
vireo work, so that would suggest you are right to raise the flag. On the
other hand, I know some PLVI can have greenish tint to the uppertail
coverts, so perhaps I need to leave some wiggle room that edges to the
secondaries are possible. And, as I said, yellow in the flanks is OK. What
is interesting about this last feature is that the amount shown in the
picture is very consistent in PLVI, i.e., those that have yellow have a
restricted spot, as opposed to a wash that runs from vent to sides of
breast.
So, I' would be OK with this as a PLVI but would also eagerly accept it as
a sp. A pure CAVI is not an option for me. "

--------------------------------snip--------------------------

Based on Matt's comments, I would like to withdraw my original opinion that
the bird is/was a Cassin's Vireo. Matt has studied these birds for years
and his opinion carries much weight with me.

As for whether the bird is a pure Plumbeous or a hybrid, I do not know,
especially in view of the conflicting descriptions from people who saw the
bird and studied it critically.

It might be worth visiting a museum to see if there are specimens of
Plumbeous Vireo which show green fringes to the secondaries. To me this
feature is fairly obvious on Noah's photos, but I also see a tinge of green
there in Jerry's excellent images.


On Fri, 5 Nov 2010 18:47:12 -0700 (PDT), Lori Arthur
<loriarthur61@...> wrote:

Hi everybody. There is apparently still a lot of discussion on the identity of
the 'Solitary' Vireo that was at Crown Beach last week, and I have seen the
excellent new photos on Flickr by Jerry Ting. In total, I probably spent more
than 2 hours observing the vireo, over the course of several days and many
different conditions. It always appeared all gray-and-white except for a small
yellowish wash around each leg.


I have to admit, Jerry Ting's Flickr photos look a lot more like the actual
vireo than my photos do. My cheap, half-broken K-Mart camera seemed to catch a
lot of reflected yellowish light in all of my pictures of the bird. Some of my
photos that I didn't post online showed MUCH more yellow than the ones that I
did post. In life, the bird certainly did not show this yellow. The only
yellowish color on it was a small patch of pale buff-yellow behind each leg, and
possibly a bit of buffy in front of each wing.


In the field, I did not notice any greenish/yellowish tint on the Crown Beach
Vireo's secondary fringes.


Interestingly, there was a report from Bob Dunn saying the vireo had "quite an
extensive yellow wash underneath" when seen in sunlight. Every time I saw
this vireo, in shade or sun, it never had an extensive yellow wash. Also, about
a month ago, an identically-patterned but very bright-colored 'Solitary' was in
the same area before the dull bird ever showed up. I wonder if that or another
brighter vireo may have stuck around to be seen by Bob Dunn.


Noah Arthur, Oakland


--
Joseph Morlan, Pacifica, CA jmorlan (at) ccsf.edu
SF Birding Classes start Nov 2 http://fog.ccsf.edu/jmorlan/
Western Field Ornithologists http://www.westernfieldornithologists.org/

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