an interesting development, and equally interesting
as to what the genotype proves to show.
As to the phenotype, Aaron brought to my attention
last Saturday the field images and I provided this
breakdown at that time.
------------------------------------------------------------------------
1. bright pink bill
2. rusty cap set off from pale face
4. pale gray, unstreaked nape
stand back from the computer screen and the bird comes
across as a Field Sparrow, at least from the front.
then there's the
1. prominent lateral throat stripe,
2. a stipling in the crown that appears to be faint streaks,
3. and the heavily streaked back
4. whitish-gray supercilium
which are Clay-colored characters
the auriculars are mostly gray (matching the gray nape) with
a warm upper border (matching the crown) ... typical Field Sparrow.
However, the auriculars are also bordered by a pale supercilium and
submalar setting them off to a degree stronger than normal in Field
and more akin to Clay-colored.
Barest hint of a median stripe is a strike against Clay-colored and
within variation range for Field. The weak, but clearly present white
eye-ring may be within variation for Field but is more typical of
Clay-colored.
and then there is the song
Field = a descending, accelerating, multi-pitch whistled sequence
Clay-colored = a steady, monotone, raspy buzz
Your bird = an accelerating, two-pitch raspy buzz
in any ID one asks whether the observed discrepancies from the
norm are within the range of variation for the species. There are a
couple of characters here that are, to my knowledge, completely
outside the range for either species
1. lateral throat stripe outside of Field
2. bright pink bill, rusty cap outside of Clay-colored
and when the variation falls intermediate between two species
(in this case including vocalizations), one finds the hybrid
explanation as likely as anything else.
Not a conclusion I come to lightly. I am aware of a Dayton area
record from the late 90's where David Dister observed a Field Sparrow
singing a Clay-colored song. However, that's not the case here.
-------------------------------------------------------------------------------------
cheers
Vic Fazio
Lawton, OK
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