[SBB] Scoring Intergrade Flickers

[Bill Bousman <[[email protected]]>]

Folks:

There have been quite a few reports of "Yellow-shafted Flickers" in 
the last few months.  Except for Mike Rogers's careful descriptions 
of intergrades, none of these reports mention why the observer 
considered the birds seen to be Yellow-shafted, rather than an 
intergrade.  Tom Grey's excellent set of photos of an intergrade 
bird, taken mid-February, is an excellent example and allows us all 
to practice our id skills and score this bird.  Quite a few years 
ago, Kurt Campbell recommended the following method of scoring.  I 
don't remember where he got the method, perhaps there are better ones 
out there.

TRAIT      YSFL(0)  RSFL(30)
Crown      Gray       Brown
Ear          Brown    Gray
Throat      Brown    Gray
Nape       Red        Brown
Shafts     Yellow     Salmon-red
Malar(m) Black       Red

The way you use this is to look at each feature and score that 
feature from 0 to 5.  You then add the scores.  For a male, a pure 
Yellow-shafted is 0 and a pure Red-shafted in 30 (for females the 
scores are 0 and 25, as the female malar is faint or not apparent).

If I look at Tom's photos, I would score the crown/forehead as mostly 
brown (4).  The ear is gray, although a little brown is leaking in 
(4).  The throat is mostly gray (4).  The nape, however is red (0), 
and the malar is black (0).  Two of the photos show a little bit of 
the tail (salmon-red), and Tom's e-mail says they were that color 
(5).  Thus, the scores sum to 17 of 30, which is a pretty mid-range 
intergrade.  Others might score this differently, but I doubt anyone 
would score it above 20.

One rarely has the views that Tom had at his birdbath and it can be 
very difficult sometimes to pick up all of the traits.  But it's worth trying.


Bill Bousman
Santa Clara County records compiler 



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