Date: 12/12/25 10:09 am From: Aaron Maizlish via groups.io <amm.birdlists...> Subject: [EBB-Sightings] Rock Sandpiper continues
All,
I just got word that the Rock Sandpiper is back at the Cerrito Creek mouth this morning. So if you regretted missing it yesterday, or you just want the opportunity to survey the county line, now is your opportunity.
It’s a great bird by the way, I had prolonged views of it yesterday late afternoon when it was terribly backlit, probably better viewing now.
To get to the bird, park in the vicinity of Central Avenue and Rydin Road, and walk about 3 blocks south along the bike path.
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eBird protocol is to record the bird from where you stand. That makes the most sense from a data quality standpoint, since the bird is part of a complete checklist. Obviously where the bird precisely is can be somewhat a matter of opinion when you’re 500 feet away. This is just the established protocol and it makes sense.
It makes no sense however to report a first county record (Contra Costa County in this case) if the bird has never physically been in that county. Most birders have the sense to adjust for this by excluding the bird from their Contra-Costa checkllst and creating a separate incidental checklist for the Alameda sighting, using their best effort to locate the pin correctly. This is not however standard eBird protocol. It would make no sense to record a Mexican bird as a US rarity and vice versa. eBird protocol is the better system except with these anomalous situations where a manual adjustment is warranted.
Aaron Maizlish
San Francisco
> On Dec 12, 2025, at 9:17 AM, Sammy Cowell via groups.io <samueldavidcowell...> wrote:
>
> My feeling is that since eBird's main purpose is citizen science/conservation, I don't think it's the ultimate end-all-be-all authority for things like county record keeping. While the eBird protocol "allows" for counting birds seen from one area while they are in another, that sort of feels against the "spirit" of county/state listing, etc. Obviously, birds don't care about arbitrary geopolitical boundaries, but some of us birders still do! If that's something you care about, the eBird protocol does provide a helpful commentary on using incomplete lists if you are purposefully emitting birds seen in different geopolitical areas: https://support.ebird.org/en/support/solutions/articles/48001059718-ebird-policies-for-special-birding-circumstances#anchorCountyListing >
> eBird is still extremely helpful to get a quick snapshot of records of the area, so if one does view the bird in a different county than their actual location, I think it would be helpful to put that in the notes for people who care about such things.
>
> Sammy Cowell
> Valley Springs, CA
>
>
> On Fri, Dec 12, 2025 at 8:36 AM Maureen Lahiff via groups.io <http://groups.io/> <MLahiff...> <mailto:<aol.com...>> wrote:
>> Expanding on Bruce’s comments, I have a question.
>>
>> I’ve had the privilege of birding along the Rio Grande in Texas, at places where one can look into Mexico.
>>
>> The trip leaders did the eBird lists for us, using hotspots in Mexico for the birds we saw on the far shore. So I have 24 birds in Mexico, observed from the US.
>>
>> Maureen Lahiff
>> (I’m not a county lister.)
>>
>> On Friday, December 12, 2025, 8:13 AM, Bruce Mast via groups.io <http://groups.io/><cathrasher4...> <mailto:<gmail.com...>> wrote:
>>
>> I'm not sure what all the consternation regarding the county line is about. Just treat the ambiguous zone as a DMZ. Per the eBird protocol, it doesn't matter where the bird is, just where you are. So you stand south of the DMZ and tick the sandpiper in Alameda, then walk north of the DMZ, start a new list, and tick the bird again in CoCo. Voila, county bird in both counties! LOL
>>
>>
>> Bruce Mast
>> Oakland
>>
>> On Thu, Dec 11, 2025 at 9:28 PM Ethan Monk via groups.io <http://groups.io/> <z.querula...> <mailto:<gmail.com...>> wrote:
>> Hi folks,
>>
>> As most all are aware, this morning Kevin McKereghan and Tera Freedman found a Rock Sandpiper at the mouth of Cerrito Creek, in the Albany Crescent. While bare part color was suggestive, additional photos of the wingstripe are out and confirm this bird as a Rock, rather than a Purple, Sandpiper. For what it is worth, a number of people have mentioned the underwing color as a diagnostic difference here. I had never heard of this so was intrigued, went home and scrolled through Macaulay for a bit and can now say I observe no difference. But maybe I am missing it.
>>
>> The bird spent much of its time sleeping, originally very close to the grassy edge where it was hidden unless you were to walk out onto the mud, and then later far out on the mudflats. The mud is shallowest north, as you get into Contra Costa County, so when the tide came up, the bird seemed to go south as the northern mudflats vanished more quickly. The creek mouth of Cerrito Creek is most productive at maybe just under a 3ft tide (there is a station at Pt. Isabel). At about 3 feet the habitat is gone, and all is to the south. In the evening the light is horrible, because you are looking west, so I would target a mid tide (~2-2.5 feet) and not later in the day, if possible, and would look from the creek mouth to maybe a thousand feet south of.
>>
>> At one point today, the bird was on the creek's north bank, but most of the time was a few hundred yards south. There are no records of this species for Contra Costa, so it would be nice to have a record there! The CalTrans signage, on their website and on the highway seem to show the creek as the county line. This includes the actual markers painted on 580 for the road crews, not just the green signs for the drivers. This has been the traditional belief of birders, too, probably because of these conspicuous signs, but as we all know there is controversy here. The Contra Costa County Assessor's Office maps the county line about 130 feet north of the creek (this varies based on where you measure from, and what the tide is doing) but the Alameda County Assessor's Office has their county line about 30 feet north of that! Today at its northmost, a few of us watched the bird maybe thirty feet north of the middle of the creek. So it was not quite there, by the two assessor's offices, but close.
>>
>> I tried to call CalTrans to figure out where they get their map data from, but I couldn't get to a person at the Oakland office.
>>
>> Ethan Monk
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