Date: 10/30/20 5:47 pm
From: Joel Geier <clearwater...>
Subject: [obol] Re: California vs Woodhouse's Scrub-Jays in OR/NV/CA
Hey Russ,

Thanks for your note. Yes, I "consolidated" the GBBO reports that were from multiple point counts on a single location, on a single day (indicated by parentheses in the column labeled "N", e.g. "1,1,2,2"), and yes, I agree these were most likely the same individuals.

About the other reports, I just sent a note to Terry Rich (based in Idaho last I heard) to ask him what he remembers about his reports.

Whatever one may think of the other reports with no details, it's worth noting the recent report from that same general area of Sheldon NWR, with photos and sonograms showing what appears to be a hybrid. It could be useful for folks to take a close look at those photos and give their views. Usually where you find hybrids, there are representatives of both parent species not too far away.

The issue with eBird filter settings is analogous to some issues that we have in western Oregon counties e.g. with reports of Barrow's Goldeneyes at Ankeny, though latitude rather than elevation is the main bugbear. Washoe County runs all the way from the Coleman Valley south to include Reno, so setting the filters to zero there would result in flagging many legitimate reports in the Reno-Sparks area. Similarly, Humboldt County runs from Denio and McDermitt south into the Grass Valley south of Winnemucca (one of the places where I think I've seen Woodhouse's in the early 2000s, not too far from one of the photo-documented records on Tom's map). Elko County covers a very large area in the NE part of Nevada, from Idaho all the way south to the Ruby Mtns and the Goshutes.

I don't really want to go into all of the eBird "records" here in Oregon that flew under the filters. I've brought up dozens of examples, including a TRUS report just a couple of days ago, but very few of those have ever been addressed. Seems like we have plenty of cleaning to do in our own house, before we worry too much about our neighbors' house.

All the best,
Joel


From: "Russ Namitz" <namitzr...>
To: "Oregon Birders OnLine" <obol...>, "joel" <joel.geier...>
Sent: Friday, October 30, 2020 4:42:59 PM
Subject: RE: California vs Woodhouse's Scrub-Jays in OR/NV/CA

Hey Joel~

I took a shot across the bow at our Nevada neighbors and for that I publicly apologize. I did not mean to cast aspersions on the birding skills of those observers. I know that you personally are familiar with some of them.

However, birding by geography is one of the very foundations of bird ID; it is something that is taken into consideration, rightly so, wherever one birds. Using geography alone is a slippery slope, and like much of bird ID, other variables should be taken into consideration.

Of the 19 Woodhouse's Scrub-Jay eBird reports from NW Nevada that are roughly within 50 miles to the Oregon border that you provided (thank you btw), only 6 reports occurred after the 2016 split of Western Scrub-Jay into California and Woodhouse's, and only 3 of those provide any sort of ID comments.

So of the 12 pre-2016 split, none have any comments of scrub-jay ID, most detections are from stationary counts and almost half of those are from stationary point counts. A quick note about the Great Basin Bird Observatory (GBBO) point counts: these reports have 2 counts for each day with different times and species lists, so there are 10 detections there, not five, though almost certainly the same individual(s).

What that means is that this data collection and bird identification took place when Western Scrub-Jay was still a single species. I suspect that observers were not paying as close attention to differentiate subspecies ID details, especially on stationary point counts where the vast majority of bird species are typically "heard only."

To me, this suggests that A) Woodhouse's Scrub-Jay is the default scrub-jay species in eBird for those NW Nevada Counties (Washoe, Humboldt, Elko) and does not get flagged as a rarity, and B) eBird perhaps included NW Nevada in the assumed geographic range of Woodhouse's Scrub-Jay when updating the 2016 split which automatically switched all of the "Western Scrub-Jay" detections in the database to "Woodhouse's Scrub-Jay."

My real point in responding to Bob's post is that I believe that the eBird filters of those NW Nevada Counties should be set to zero for Woodhouse's Scrub-Jay, prompting users to write identification comments at the very least.

Cheers,
Russ Namitz




 
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