Rosy-Finch Identification Can Be Tricky!

[Rosyfinch]

Rosy-Finch identification can be tricky!
Here is an ID Challenge--
Charles Howell took 5 pictures of the same bird that visited Crest House deck feeder on
March 17, 2004.  Its bill is darker, something we see late in the winter. The bird could be
either a first year Black or a first year Gray-crowned.  Our impression is that by March the
immature Gray-crowns show a certain amount of nice chestnut or cinnamon or rufous color,
especially around the neck and back.  Rosyfinch photo #5, #4 and #2 all hint at this color,
while #1, and to some extent #3 seem to show almost black centers to the contour feathers,
suggesting it is indeed a Black. However, even immature and female Black Rosy-Finches
often show quite a bit more pink on the wings and lower belly than exhibited in photo #5,
again suggesting it is a Gray-crowned.  Notice a hint of gray cheeks in #2 and #3-- could it
be an immature coastal (Hepburn's) subspecies of the Gray-crowned?  Now look at the
color of the wood on the feeder and see the effect that exposure or photo editing has on its color!

Our banders have shown that it may be impossible to ID some of these "indeterminate" birds
in the field.  We had been calling them immature Blacks but almost half turned out to be Gray-
crowned, based upon feather studies in the hand.  Exactly which feathers or groups of feathers
were diagnostic, I do not know, but will be interested to learn.  When we had a bunch of Brown-
capped juveniles last year (along with lots of Black immatures and what we thought were a few
Gray-crowned), we called them "buffies," often deciding we could not tell between Brown-
capped and Gray-crowned.  Now, this winter, without any Brown-caps, we are realizing that
the "buffies" may have also included some Blacks as well!
CLICK ON PHOTO LINKS FOR LARGER VIEWS.  LET US KNOW WHAT YOU
THINK ABOUT IDENTIFICATION AS TO SPECIES.  (Replies follow the pictures, below)

Photo #1	Photo #2	Photo #3	Photo #4	Photo #5

VIEWER #1:
Could it be a cross between a gray-crowned and a black?

VIEWER #2:
There was an interesting article recently from Hilton House.  It was about using a conversion
to black and white  and then critically comparing images.  In their case it was perhaps House
and Purple finches.  Could this gambit help you with separating indeterminate birds.  You might
need B/W images of known birds as a reference.  It seems strange to revert to B/W but it might
help to focus on shape rather than color?  Not having seen any of your Rosy Finch species,
my idea might be useless...
 
VIEWERS #3 & 4
(Not knowing that all the pictures were of the same bird,) we took a look at these
photos and here's what our opinion is! This was just our guess...the photos look of separate birds...
 
1. Black Rosy-Finch
2. Gray-crowned Rosy-Finch (Hepburn's)
3. Gray-crowned Rosy-Finch (Hepburn's)
4. Gray-crowned Rosy-Finch (Hepburn's)
5. Gray-crowned Rosy-Finch (Interior)
  
Steve Cox, of Rio Grande Bird Research, who supervises the banding at Crest House:

Looking at primarily photo 5, I would be inclined to call this bird a second year, Gray-crowned.
I based this on the what appears to be the extensive cinnamon undersides, cheek and neck.
I really can't get a good feel for the bill color.  It looks dark, in most of the photos but, I'm not
sure because of the focus and lighting.

I know this will not help with the ID of this bird but when we have a bird in the hand some of the
things we now take into consideration is: bill length and wing chord.  However, there is overlap
between species.

On average the bill length  is  longer on the Gray-crown with the coastal race being slightly longer
(again on average).  Wing chord is much the same.  There are some age differences with primary
covert feathers and overall molt limits of the medium and greater coverts. The coloration of some
feather tips of the lesser and medial coverts can help in determining the sex.  Yellow to orange for1
female and pink for male.  Also wing length will give us a clue.  This info can be gleaned from
Pyle's "Id Guide to North American Birds"