I operated a pelagic trip in Monterey today and there are hundreds of Black-vented Shearwaters there right now, and we saw two Manx. But it is clear that the Black-vents are massively moving north right now. Also on the 10th there were a lot of them in Morro Bay where they are not always around at this time of year in most years. This is a year when there will be more in SF county, absolutely no doubt in my mind.
Their move northward has little to do with El Niño though, the main effect of the El Niño happens entirely outside of the distribution of Black-vented Shearwater. What is more likely the case here is the marine heat wave in Mexico/southern California. Or inshore warm water moving north, which can happen in fall/winter in what is known as the Davidson Current. But this is separate from El Niño. There may be correlations, or what they call “teleconnections” but these are different events, and it is good to try and keep them separate as sometimes we can have marine heat waves entirely outside of El Niño years, and they can show some similar effects.
From: <SFBirds...> <SFBirds...> On Behalf Of Brian Fitch via groups.io
Sent: Wednesday, September 16, 2026 8:28 PM
To: <SFBirds...>
Cc: SF Birds <SFBirds...>
Subject: Re: [SFBirds] Black-vented Shearwater
While scoping around 8 AM, the B-v Shearwater entered my view, and I was able to follow it long enough to see the discerning field marks and flight style. It flapped a lot with quick wingbeats, and glided/sheared some, showed relatively short, somewhat rounded wings, had more body length in front of the wing, while appearing a little back heavy in the shorter rear portion. The plumage was brownish dorsally and on the vent, while the belly and underwing were off-white, and the throat/neck were muddy white-brown. It stayed low over the surface, banking a little as it flew off southward. Unlike August of '25, when the only other northern sighting was a single bird in Monterey County shortly before mine, there have been many Black-venteds moving up the coast for some weeks, with as many as 30 spotted yesterday off of the San Mateo coast. If the movement continues northward, as in the last super-Nino, they could be present in numbers off of SF soon.
There was also a big increase in Parasitic Jaegers, with roughly 15 mostly white morphs harassing terns, gulls ,and each other. Over at North Lake in GG Park, the Northern Waterthrush found yesterday by David was still present, mostly at the south end, but also near the north island. And David's Chestnut-sided Warbler was still present in early afternoon at Dragonfly Creek, visible from the nursery and the trail on the other side of the riparian area.
