Re: County Bird List Update & Sage Sparrow Difficulties

Jamie Chavez
 

I've had a couple of replies saying the link to Kimball's message posted on
ID Frontiers didn't work. Rather than me trying get this linked correctly
his reply is pasted below. Sorry for the confusion.

--
Jamie Chavez
Santa Maria, CA

-------------------
Jamie,

Your Santa Maria bird certainly looks like a good candidate for *Artemisiospiza
nevadensis* (Sagebrush Sparrow) – the sharp and extensive dorsal streaking,
the relatively thin malar (with white mixed in with the black in the
anterior portion), and possibly the longer primary extension (hard to tell
from the photos, and maybe not reliable in the field) all support that ID.
Also, I’m guessing that pale “Sage Sparrows” on the coast of California in
late fall and winter are far more likely to be highly migratory Sagebrush
Sparrows than *canescens* Bell’s Sparrows. Mojave desert *canescens* move
widely through the mountains of Los Angeles region after breeding (roughly,
May through summer), but I don’t know of any evidence that they move over
the mountains onto the coastal lowlands.

In Los Angeles County the only coastal specimens of “pale Sage Sparrows”
are November birds from the San Fernando Valley (coastal lowlands) and San
Clemente Island; both of these measure out to *nevadensis*(and plumage is
also consistent with Sagebrush Sparrow). This despite the fact that *
canescens* is a common breeder on the desert slope of the county and
wanderers into the mountains (post-breeding) regularly. I would guess that
San Joaquin Valley *canescens* behave similarly, with limited post-breeding
dispersal but no long-distance movements to the coast.

Yes, the eBird data will be a mess until the next eBird taxonomic updates
and a lot of scrutiny of the existing data entered under the now
paraphyletic category of “Interior Sage Sparrow (*canescens/nevadensis*).”

I suspect that with the publication of the AOU checklist supplement in the
July *Auk* there will be lengthy discussions on this list serve of the
characters that separate *canescens *and *nevadensis* in the field. It’s a
work in progress, and certainly won’t be easy, given that measurements may
be the most reliable way to separate them (*nevadensis* being larger).

Kimball

Kimball L. Garrett
Ornithology Collections Manager
Natural History Museum of Los Angeles County
900 Exposition Blvd.
Los Angeles, CA 90007 USA
213-763-3368
kgarrett@...
http://www.nhm.org/site/research-collections/ornithology

*From:* NBHC ID-FRONTIERS Frontiers of Field Identification [
mailto:BIRDWG01@... <BIRDWG01@...>] *On Behalf Of
*Jamie Chavez
*Sent:* Wednesday, June 26, 2013 7:03 AM
*To:* BIRDWG01@...
*Subject:* [BIRDWG01] Sage & Bell's Sparrow ID

With the pending split of Sage Sparrow I wondered if anyone had an opinion
as to the identity of a bird I photographed in October 2006 in coastal
Santa Barbara County, CA. Since this bird shows significant streaking on
the mantle and a weaker black moustachial stripe it is clearly not a
coastal Bell's Sparrow. However, It seems to me there will be potential for
confusion between the CA "interior" canescens, now to be lumped with belli
rather than nevadensis, and a true interior Great Basin Sage Sparrow which
shares similar physical traits. In particular, the amount of streaking on
the mantle. How reliable or variable is this for separating these two?

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