Greetings all,
In recent days I've been sent photos of two different presumed hatch-year (HY)
sapsuckers with somewhat ambiguous features. In both cases I think that there
is at least moderate evidence that suggests they are hybrids rather than "pure"
Yellow-bellied and Red-naped, which is how they have been identified. One of
the birds is from Texas and the other is currently being seen in Tillamook
County. I have reached out to Marshall Iliff and Shawn Billerman for some
guidance on these birds (see my email to them is below). Shawn did his PhD
studies on how Red-breasted, Red-naped and Yellow-bellied Sapsuckers interact
across their broad zones of contact during the breeding season. These three
species are all known to interbreed with one another and their offspring are
fertile and can produce backcrossed hybrids.
It is of course well-known that Red-breasted and Red-naped sapsuckers cross
breed rather freely along a long suture zone of contact that extends from
northern California into British Columbia. Probably less known and certainly
less publicized is that Red-breasted and Yellow-bellied sapsucker breeding
ranges overlap and they also hybridize, to what extent is poorly known. I
strongly suspect that the Texas bird in the attached photo is a Yellow-bellied
Sapsucker X Red-breasted Sapsucker hybrid, even though local birders there have
been identifying it as a "pure" Yellow-bellied. In my opinion the back pattern
is wrong for Yellow-bellied and I can't find any evidence that pure
Yellow-bellieds ever show irregular patches of red through the auriculars. In
my experience this sort of random red bleeding across the black and white
facial striping is found strictly on birds that have some Red-breasted
Sapsucker ancestry.
The Tillamook County bird is much more ambiguous. Aside from quite a bit of
what appears to be retained juvenile plumage on the underparts, which most
references say should have been replaced by this date, this bird looks pretty
good for Red-naped Sapsucker. It shows no random red in the face pattern, which
is typically evident in in any Red-naped X Red-breasted hybrid. That said, the
bird does appear to have a little bit of red on the sides of the upper breast,
which should not be the case with a pure Red-naped. I can certainly appreciate
how those who have seen this bird are calling it a Red-naped. It may well be a
F2 or F3 hybrid with Red-breasted ancestry from a few generations back.
Given how challenging it is to be certain of the parentage of some apparent
hybrids, we can't assume that all hybrids seen in Oregon are Red-breasted X
Red-naped. It is certainly plausible, and in my opinion likely that some of the
apparent hybrids we get here are Red-breasted X Yellow-bellied crosses. At this
point we are not really left with a good option when it comes to slotting a
bird for whom the parentage is murky. I would like to see Marshall add
"Sphyrapicus hybrid" to the taxonomy to provide a better option than just
listing them as "sapsucker sp." In both cases I feel confident that these birds
are hybrids (perhaps F2 or beyond), but my level of confidence about their
parentage is much lower.
I hope to get some good feedback from Shawn and perhaps Marshall. If I do, I
will certainly share it. Feel free to forward any troublesome sapsuckers that
you find in your review queues. Years ago when I was doing regional editing for
North American Birds Steve Mlodinow and found that quite a few of the Red-naped
Sapsuckers being reported west of the Cascades were RBSA X RNSA hybrids, hence
reports of them need be reviewed carefully and probably should be supported by
photos before we accept them.
Dave Irons
________________________________
From: David Irons
Sent: Monday, December 20, 2021 9:48 PM
To: Marshall Iliff <mji26@xxxxxxxxxxx>; Shawn Billerman
<s.m.billerman@xxxxxxxxx>
Subject: Two interesting sapsuckers and how we slot them in eBird
Greetings Shawn and Marshall,
In the past five days my opinion has been solicited about the parentage of two
apparent Sphyrapicus hybrids. One was sent to me by Mary Gustafson (image
attached). This bird is wintering Laredo, TX and many local birders there are
identifying it as a "pure" Yellow-bellied.
The second, which can be viewed by doing current image eBird search of
"Red-naped Sapsucker" (Tim Janzen
S99157903<https://ebird.org/view/checklist/S99157903>) is being seen in
Tillamook, Oregon and it has been identified as a Red-naped Sapsucker.
In both cases the birds seem to have significant retained juvenile feathering
on the underparts. Based on my understanding of molts, only Yellow-bellieds
should still be showing extensive juvenile body feathering this far into
December. That said, when I search December eBird photos of apparently "pure"
Red-naped Sapsuckers I am finding lots of photos of birds that show either a
complete lack of a black breast shield/throat frame or a mottled version of
such and patterns on the underparts that are suggestive of retained juvenile
feathering rather than a more adult-like plumage.
On the Laredo bird the red in the face behind the eye is bleeding across the
black auricular and into the white supercilium and moustachial stripe, which to
me suggests at least some Red-breasted Sapsucker lineage. Further, the narrow
trough of the whitish barring on the back is more like the pattern shown by a
Red-breasted and not nearly as extensive as I would expect on a pure
Yellow-bellied. I told Mary G. that I thought it was likely a YBSA X RBSA even
though it shows no apparent red on the breast. This bird also shows no red on
the nape, so I am inclined to think it's not a RNSA X RBSA.
The Tillamook bird is interesting in that it looks mostly like a Red-naped even
though it has a more juvenile-like pattern to the underparts. I am not seeing
any red in the face pattern, which in my experience is pretty much a given with
RBSA X RNSA hybrids. However, there is some red on the sides of the upper
breast outside of the expected red on the throat, which does suggest some
Red-breasted ancestry. Is there evidence of RBSA X RNSA hybrids pairing with
YBSA and producing offspring?
My first three questions are primarily to you Shawn. Can and do HY/first-winter
Red-naped Sapsuckers retain more juvenile feathering than some of the recent ID
articles on this topic suggest? Secondly, do some RBSA X RNSA hybrids not show
any unexpected red in the facial pattern? Finally, can apparently "pure"
Yellow-bellied Sapsuckers occasionally show unexpected red in the face pattern?
I can't find any evidence of such in the eBird photo galleries.
The real challenge with birds like these is how do we account for them in eBird
checklists. As a reviewer I would not accept either of these birds as reported.
Further, based on some of the age-related confusion discussed above, I would be
equally reluctant to accept them as definitive hybrids of known parentage. I
think at best these birds can be treated as "Sphyrapicus hybrids," but there is
no available taxonomic slot in the eBird taxonomy to put them into. With
hybridization between RBSA and RNSA being arguably more studied and better
known among rank-and-file birders than hybridization involving YBSA, I think
birds that do present as hybrids (particularly in here in the PNW) get
identified almost by default as RBSA X RNSA with no real consideration of
potential YBSA ancestry. The more I look at these birds (like Cackling Goose
subspecies) the more uncertain I become about what I looking at.
I look forward to your thoughts on these birds and perhaps some better guidance
on how to deal with eBird reports of presumed hybrids with ambiguous outward
appearance.
Dave Irons
Attachment:
IMG_2931.jpeg
Description: IMG_2931.jpeg
