Date: 9/16/25 4:01 pm From: Marty Freeland via groups.io <martinf3...> Subject: [pen-bird] Recent notes: Bell's Vireo and eastern vagrants
Hi all,
The past week has been fantastic on the San Mateo coast! Highlights have included a Bell's Vireo, a Red-eyed Vireo, a Northern Parula, a Black-and-white Warbler, an American Redstart, and a couple Tennessee Warblers. The biggest highlight, however, was being there for Chris Hayward's milestone 400th species for San Mateo County, and a county bird for Malia too. Many, many congratulations to Chris!!!
On 9/10, migrant numbers were rather low on the south coast. Occasional showers of rain were unexpected in September and it was windy for much of the day as well. There was a large inshore movement of seabirds immediately off Pescadero SB in the morning, with Sooty Shearwaters passing at a rate of 100 every 3–5 seconds for at least half an hour and also including 8 Parasitic Jaegers, 12–15 Sterna terns of which at least 3 were Common, several hundred Elegant Terns, and immense foraging concentrations of other common inshore species. Late in the morning a Tennessee Warbler was with a large flock at Water Ln in Pescadero.
On 9/11, migrant numbers were fair but patchy on the north coast. I was happy to note 4 Warbling Vireos over the course of the day and higher numbers on subsequent days. For the last week of August and first 10 days of September I was averaging less than 1–2 Warbling Vireos per day on the coast, which is truly ridiculously low, but since 9/11 numbers have picked up somewhat and while still slightly below average, they are not that far off. It is apparently a very good year for this species in some inland areas and in the Mojave. 3 gray-headed Orange-crowned Warblers at Mussel Rock Park was a high count. In the early afternoon I was surprised to see a Nuttall's White-crowned Sparrow carrying food and to hear what seemed to be the transfer of food to dependent young in thick willows along Denniston Ck. I could not see the recipients of the food to age them more precisely, but watched the same adult take mouthfuls of insects in several times over a few minutes and heard brief bursts of loud begging vocalizations from the same spot each time. Nuttall's White-crowns can (rarely) raise as many as 4 broods per season and nesting activity can run quite late, but apparent feeding of young after the first week of September still feels rather remarkable, and in this case I thought there was at least a chance that the young in question might have been nestlings. In the late afternoon, a female Black-and-white Warbler was in the Arroyo Leon riparian accessed from the north end of Johnston Street in Half Moon Bay. The same general area can also be birded from the bottom of recently reopened Carter Park.
On 9/12, numbers of migrants on the south coast were up and included a selection of rarities. Early in the morning at Ano Nuevo a female-type American Redstart was on the outer part of the point; this was the county's fifth this fall and there has been one more since for a total of 6 to date, which is a good number. A hatch-year Red-eyed Vireo was with a large flock along Whitehouse Ck. While trying to figure out access to the tall willows near the mouth of Cascade Ck in northern Ano Nuevo SP, I found a Bell's Vireo working a large patch of poison oak. My camera began to malfunction while I was looking at the bird and I had to drive 20 minutes north to get cell service and spread the word, so by the time I returned to the spot I had only very marginal documentation and the bird was no longer showing. Fortunately, after an hour or so of effort in a stiff NW breeze, a group refound the bird at the original location and Chris, Malia, Ryan Mense, and others obtained excellent photos. This Bell's Vireo is the fourth record for San Mateo County and the first to occur on the coast, as well as the first to occur in fall. Previous records are 4/5/1905 (collected by Chase Littlejohn in the city of San Mateo), 5/17–6/2/2010 (Peter Metropulos et al. at Bedwell Bayfront Pk), and 5/14/2015 (Ron Thorn at Sem Ln). All four records, including the one this week, appear to pertain to the dull westernmost subspecies, which breeds in California. Late on the same day, another bright Tennessee Warbler was with a flock on lower Tunitas Ck.
On 9/14, the first Black-throated Gray Warbler I have noted this season was on a survey at Tomkat Ranch in Pescadero, along with the county's most coastal resident Oak Titmice. Later in the morning, a Nuttall's Woodpecker—notable on the immediate coast—was in the willows behind Mariner's Church in Half Moon Bay. During the afternoon, I birded the northern and central parts of the coast with Chris Henry. Migrant numbers were decent across the board and especially good at Mori Pt and from Tunitas south. In the late afternoon, we had a male Northern Parula at the Stage Rd bridge over San Gregorio Ck. Passing through again an hour later we could not relocate the tailless Chestnut-sided Warbler that Chris Hayward found at the same site in the interim.
So far the San Mateo coast has been having a great fall! As always, further details, GPS coordinates, photos, etc., are on eBird for all rarities.
