Date: 10/30/26 1:45 pm From: Eli Gross via SFBirds <a.eli.gross...> Subject: [SFBirds] Identification of the Sapsucker at Elk Glen Lake
Hi all,
This male sapsucker, which was found by Travis Smith on 10/18, has been
seen and photographed by many and it seems likely it will winter in the
area. It's been reported as a Red-naped, which while borderline, is what I
personally thought it was when I first saw it in the field. But in
reviewing my photos after the fact it showed a couple of field marks that
seem outside the range of variation for a pure Red-naped and point towards
the influence of Red-breasted Sapsucker genes. The features that gave me
pause for a "pure" red-naped were:
- The amount of red in the back end of the upper white facial stripe
- The amount of red in the nape is a bit more broad and messy than
normal and creeps into the black bar dividing the red of the nape and crown
(though it doesn’t connect).
- Additionally, the amount of red behind the eye seemed a bit extensive
for a Red-naped but potentially still within variation for a pure bird.
- The breast pattern is good for adult male Red-naped with an incomplete
black border around the red of the throat and upper breast with the red of
the breast meeting the white of the lower white facial stripe and a clean
black bib beneath the red of the throat
Sapsucker identification is notoriously messy given how much hybridization
there is amongst Red-breasted, Red-naped, and Yellow-bellied, so I reached
out to a few others to see if they agreed with my take, including Shawn
Billerman who is a PhD at the Cornell Lab. He has done an extensive amount
of work studying hybridization in Sapsuckers, including specifically on the
hybrid zone between Red-naped and Red-breasted Sapsuckers. His take on this
bird is included below:
"I’d probably call this bird a hybrid, though it is likely at least
backcrossed with a Red-naped. One feature that I always keyed in on for
hybrids is how the red of the nape patch connects to the crown, basically
creating an isolated black nape patch. It’s not complete in this particular
individual, but there is definitely some pattern there, and in this
individual it looks like a dotted line connecting the red of the nape to
the crown. By itself, the red on the face and auriculars is not outside of
the range of variation for Red-naped Sapsucker, but I think taken with the
extensive red on the back of the head, and how the two almost connect as
well, I’d lean towards hybrid."
So, in summary this individual is better identified as a hybrid Red-naped x
Red-breasted Sapsucker, or sapsucker sp, for eBird purposes. My apologies
for not getting the word out on this sooner as I know some folks made
significant effort to come see this bird given it had initially been
identified as a "pure" Red-naped. For anyone who's interested in reading up
on the work Dr. Billerman and others have done on Sapsucker hybridization,
I'd be happy to point you to those scholarly articles off list.
