Date: 9/28/25 9:48 pm From: Marty Freeland via groups.io <martinf3...> Subject: [northbaybirds] Yellow-green Vireo and other notes
Hi all,
After a rather lackluster morning on the OP (I saw the continuing Lucy's and Blackpoll at Fish Docks and a late Western Kingbird at the lighthouse; I did not check Upper Willows and so missed the Eastern Wood-Pewee later found there by Ethan Monk), I birded riparian from Inverness to Muir Beach for much of the day. I was impressed with the number of western migrants in general. Especially impressive were the numbers of Nashville Warblers (6–8 over the course of the day), Cassin's Vireos (~4), and Black-throated Gray Warblers (on average 1–2 per flock). I do not have the strongest frame of reference for the numbers of these migrants expected at the spots I was birding, as I rarely sink time into west Marin riparian in late September, but I would be shocked to note these numbers in San Mateo County (for instance) and I would imagine that even for west Marin they feel at least somewhat noteworthy. Additionally, Wilson's Warblers were in most flocks and Western Flycatchers and Warbling Vireos (up to three of the latter) were with many flocks as well. I only saw 3 Yellow Warblers, all in the Inverness area.
The major rarity highlight was a beautiful Yellow-green Vireo in Bolinas with a small flock. I stopped to check a small group of chickadees without high expectations and was absolutely gobsmacked to see a reverse Austral migrant lemon-yellow megavireo hanging out with a Chestnut-backed Chickadee and a Ruby-crowned Kinglet!! There are, rather remarkably, 6+ prior records solely from the area immediately around Bolinas Lagoon. It is shaping up to be a strong year for this species in California.
Later, a Chestnut-sided Warbler was with a large flock in Volunteer Canyon, birded from the beginning of the dirt road on the southeastern side. A Tennessee Warbler was in riparian by the main beach parking area in Stinson Beach and another one was in Muir Beach. This species is having a great fall regionally.
Photos, coordinates, and additional details are on eBird already for some things and will be soon for the rest.
