Date: 6/21/25 6:34 pm From: Eddie Bartley via groups.io <eddie...> Subject: [SFBirds] Southern Waterfront breeding bird miscellany
Super cool on the first SF breeding record for Blue-gray Gnatcatcher in the "re-created" hollow in the Presidio, thanks for sharing that good news Dom.
Due to the general lack of open space and pittance of quality habitat on the east side of SF (relative to the central ridge and west), breeding of birds is much suppressed on this side of town. Also, it appears the ever burgeoning Raven and Crow populations have eliminated much in the way of backyard songbird breeding compared to 20 years ago. These clever corvids are really good at finding nests.
Any bird breeding activity is something to celebrate so I'm adding a few seasonal observations from our Southern Waterfront area ramblings for any folks interested in this sort of thing.
*Aqua Vista Park:* About 5 years ago, at some expense and with good intentions the Port of SF installed a Caspian Tern "platform" replete with tern decoys and audio playback (until the solar panel powering it was stolen about a year later). The idea was to replace the dilapidating pier that the terns had adopted and successfully bred at for at least a decade before it finally collapsed during winter storms. Unfortunately the terns never took a liking to the new platform having likely lost their homing mechanism in the two (or 3?) years between the old pier collapse and the new platform installation. The decoys are still there, most all listing on one side now. Noreen and I take a look each spring a time or three in hopes (though less and less each year) that they will re-establish. So it was a fun surprise on two recent visits to see a pair of *BLACK OYSTERCATCHERS* take up territory on the platform. One at a time sitting for long periods of time as if incubating in the exact same location sheltered in part from one of the listing decoys. Quite exposed but who knows, might could work. Coincidentally maybe, this is the first year that we have not been able to detect Black Oystercatchers making a breeding go of it at Heron's Head Park. First noticed an oyster-let there during a butterfly survey about 10 years ago on the dilapidating Lashlighter Pier, which completed it's collapse about four years ago. Oystercatchers then took to breeding on the roof of the Recology recycling center (with many, many Western Gulls) which probably made for an ever-greater exciting first flight for any surviving oyster-lets. Despite those odds, most years in the past ten we've usually seen a young darkish-billed juvenile Oystercatcher foraging along the rip-rap at Heron's Head. Nature can be super resilient that's for sure!
*Red-winged Blackbirds, India Basin & Pier 94:* another interesting breeding adaptation is the apparent move of a breeding colony of RW Blackbirds from the very east end of India Basin to Pier 94. Up until the early 2010's at least RWBLs nested in a patch of willows until "The Shipyard" developer apparently decided those willows must go. Maybe they didn't like the occasional campers. Not too long after that, and shortly after the uplands portion of Pier 94 was raised with dredged materials and planted with some natives, a few RW Blackbirds began attempting to nest in the Coyote Brush and Toyon there. We've seen young over the past few years but never as many as this year. Per our eBird reports: seems a few (and only) males show up beginning early December, then more and more males until some females join them about March or April when courtship and nesting is taken on in earnest. We've been out much of June so haven't visited this month but my highest estimate yet was at least 32 individuals with at least 8 young on May 26. Probably many more since, to keep disturbance to a minimum, we tally moving quickly dodging perched alarming males.
*White-throated Swifts:* speculative at this point but this past month we have seen several WTSW from the elevated section of I-280 between Caesar Chavez & the 101 split. Could be that they are nesting in the weep-holes on the under-beneath of the freeway - a well documented breeding adaptation of these aviation specialist.
