Date: 4/19/25 9:38 pm From: basquebirder via groups.io <allaboutbirds...> Subject: [SFBirds] San Francisco Biking Big Day 04/18/25
Howdy SFBirders,
Yesterday 04/18, Josiah Clark, Jaime Chavez and I set out on an all day effort to see as many species of birds as we could within San Francisco county...by bike. The weather conditions were perhaps not most ideal, but with the lack of prominent winds in the morning, and some sun that popped out around noon, we were happy with what we were presented with.
The gist of the route was to start at Lake Merced in the night until just past dawn, then Ft. Funston, ride up Sunset Dunes Park to the Cliff House, ride through Golden Gate Park before climbing up Mt. Sutro over to Twin Peaks, down Glen Canyon, whereafter we hoofed it over to the county line at Candlestick Pt. SRA, then worked our way up the entire SF bayside to the Presidio, where we ended at Mountain Lake Park.
I'll give a more thorough run through the route and species composition below, but we started at 5:30am and ended just before 9:00pm, riding around 50 miles, which resulted in a satisfying total of 137 species.
Highlight birds of the day (in taxonomic order) were: Greater White-fronted Goose, Gadwall, Vaux's Swift, both rails, Ring-billed Gull, Thayer's Gull, Olive-sided Flycatcher, Cliff Swallow, Wrentit, Ruby-crowned Kinglet, Fox Sparrow, White-throated Sparrow, Lincoln's Sparrow, Orchard Oriole, Bullock's Oriole, and Lazuli Bunting.
Notable misses were: American Wigeon, Band-tailed Pigeon, Long-billed Curlew, Short-billed Dowitcher, Sharp-shinned Hawk, Barn Owl, any falcon, Western Flycatcher, Warbling Vireo, House Wren, and Pine Siskin.
Read on below for the specifics of the day.
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Josiah and Jaime met me at Sunset Circle on the north side of Lake Merced at 5:30am. Our first mission was to hear any owls, but more importantly coax in some rails. The wooden bridge provided 3 Virginia Rails and even a Green Heron calling! Turns out the gate through the golf course is closed at night, so we rode along Lake Merced Blvd. and Skyline Blvd. to reach the boathouse, before heading down to the concrete bridge for dawn. The passerine chorus had already started, with our first Spotted Towhees, Bewick's Wrens, yellowthroats, and Marsh Wrens of the day. Before reaching the bridge, we managed to coax a Sora to call near Gun Club marsh, as well as unintentionally flushing our first Great Blue Heron of the day. Great-tailed Grackles are always obvious and easy but are a necessary bird on an SF big day, and were performing well per usual at the bridge. We scoped the lake, ticking our first Ruddy Ducks, Clark's and Eared Grebes, and both Tree and Barn Swallows. However, we felt we had seen most of what could be easily seen here, so we jammed up to Ft. Funston for some seawatching.
We went straight to the platform, where the swell and visibility we quite favorable to see what was going on. Numbers of seabirds overall were not impressive, but perhaps more than I've personally seen offshore in recent days. The numbers of shorebirds were great though, with hundreds of Whimbrels and Sanderlings lining the shore up Ocean Beach. We added our first Marbled Godwits, Least and Western Sandpipers, 3 species of loons, Pigeon Guillemots, Common Murres, Caspian Terns, Western Grebes and 3 species of cormorants. Before dropping back down to Lake Merced, Josiah made the suggestion to quickly check the nursery by the southern parking lot, and I'm so glad he did because the sparrow flock there provided our first and only Lincoln's and Fox Sparrow of the day. Lincoln's tend to be hard to come by this late in the season, and so do Fox, but myself and many other observers have noted how few Fox Sparrows there have been in recent months along the Peninsula and perhaps Bay Area wide, so we felt lucky to chance upon this one.
We dropped back down to Lake Merced and did a quick run through the boathouse and back over the wooden bridge. An impressive flock of migrant swallows must have been pushed down the night before, with well over 100 Tree Swallows mainly composing this group, swirling low over the golf course feeding on the visibly abundant insect swarms. We added our first Violet-green Swallows and Northern Rough-winged Swallows there, as well as Allen's Hummingbirds. I thought I heard a Pine Siskin calling right there as well, but we never heard it again, so it was a tantalizing encounter of a bird we ended up missing today.
We basically took Sloat down to the recently closed Great Highway, where we checked the ocean as we kept on moving north to the Cliff House, adding the Snowy Plovers off Lawton. The Cliff House was our last chance for any more seabirds so we made the most of it. The rocky shorebird trio (Black Oystercatcher, Surfbird, and Black Turnstone) were showing quite nicely below the Camera Obscura, as well some nearby Short-billed Gulls and Willets, but nothing new to add offshore.
We left the immediate coast and journeyed into Golden Gate Park. Our first stop was North Lake, but only after chancing into a pair of Cooper's Hawks and our only Ruby-crowned Kinglet of the day in a random flock on the way. We were greeted by everyone's favorite flying tea kettle, with dozens of Cedar Waxwings whistling in the eucalyptus above, and Josiah spotted a first-year male Bullock's Oriole nearby. Soon thereafter a female Western Tanager joined the oriole! Both of those ended up being the only ones of the day for us. We also picked up our first Ring-necked Duck and Belted Kingfisher. We checked the Polo Fields and then hit Spreckels Lake, where a lingering Thayer's Gull was floating around by the turtle sculpture in the water. Lloyd Lake only provided our first Turkey Vulture of the day, and a reminder that things were beginning to warm up and that we needed to get a hilltop sooner than later. Blue Heron Lake ended up being a pretty quick check, which granted immediate views of the continuing Greater White-fronted Goose by the boathouse. We meandered from there through the Rhododendron Dell and Lily Pond, and ended at the Oak Woodlands and the top of Arguello. Bird activity was still going strong, and we were immediately serenaded in by a White-throated Sparrow at the horseshoe pits, followed by Josiah hearing our first Black-headed Grosbeak of the day, followed by me getting us on a buzzing male Lazuli Bunting. It was an exciting couple minutes there. There were also around 7-8 Orange-crowned Warblers there, so it seemed like the migrants were mostly in the warm, tucked away parts of the city, giving us hope for Glen Canyon coming up.
We left the park and ascended our only major hill of the day: Medical Center Way behind UCSF, taking us to Rotary Meadow. Although we knew it would take some amount of time to climb it and bird it, the species possibilities were motivating. We reached our first overlook before Rotary Meadow, hoping for a Band-tailed Pigeon to fly over, or an early Swainson's Thrush to whit below, or even a Rufous Hummingbird quickly passing through to lap up some twinberry nectar. Alas, none of those birds showed for us, but Josiah expertly spotted a distant Olive-sided Flycatcher sallying at the top of one of the tallest eucalyptus across the valley. Nothing more added at the meadow itself, except for this mystery raptor that left us befuddled (Sharp-shinned like, but everything about it seemed off).
We crossed Clarendon next and climbed a small hill next to get to the reservoir at Twin Peaks. The conditions for a skywatch were excellent! But fleeting...We could see the fog creeping in quickly and the stillness of the morning broken by W winds starting to get stronger. Nonetheless, obvious flight was happening with 10 or so flocks of 30+ waxwings each moving north and multiple swirls of swallows, where we managed to pick out our only Vaux's Swift of the day. More Turkey Vultures were moving through as well, but raptors were lacking. We also kept on looking down towards Laguna Honda Reservoir, where Josiah and I had just seen Band-tailed Pigeons a couple days before on the job, but no dice today. We refueled with some food while watching, and began our descent to the bayside, but not before going through Glen Canyon.
Glen Canyon was as predicted a warm bowl, protected from the wind and in the sun. Passerine activity was decent, and with some coaxing were able to see several flocks with multiple Wilson's, Orange-crowned and Townsend's Warblers. We added our only Hermit Thrush of the day deep in the willows. We almost made our way to the recreation area at the far east end of the canyon, but decided to check the willows one last time. Our perseverance paid off with a total surprise adult male Orchard Oriole that stealthily made itself visible in the willows! It provided great views and quietly made its 'chuk chuk' call. We were stoked! It was only 2:30pm and were already at 109 species without having visited the bayside yet. We picked up some Banh Mi sandwiches, and began a straight shot to the county line.
Arriving at Candlestick Pt., we added a fortunate Osprey on our way south. The tide was pretty high, so mudflat was limited. But bay ducks made up for it, adding our first Buffleheads, Lesser and Greater Scaup, and Red-breasted Merganser. Spotted Sandpipers were numerous on the concrete pilings. We hugged the shore north to Yosemite Slough, where looking offshore we saw our only Elegant Terns and Horned Grebe of the day. All the shorebirds were huddled at the little mudflat on the west end of the slough, including our first American Avocets, Dunlin, Black-bellied and Semipalmated Plovers, and Greater Yellowlegs. The Revere St. pond produced for us as well adding our first Black-necked Stilts, our only Great Egret of the day, and a pair of Gadwalls! It seems these birds hadn't been seen here since January, so that was fortunate! I was ready to keep riding north, but Josiah insisted to check out the slough one more time, and I'm so glad he did because we added our first Killdeer and our only Western Meadowlarks of the day in the fields on the north side of the slough. A good reminder to scrutinize every worthwhile patch.
We climbed up the Ingalls Rd. hill (a short but very steep hill by bike) over to India Basin, where then on adding new birds became serious work. We were looking for a Ring-billed Gull among all the California Gulls, a Long-billed Curlew in the pickleweed among the Whimbrels, a lingering Common Goldeneye among the scaup, or some American Wigeons dabbling in the shallows. Well out of all those, we only managed to pick out a first-year Ring-billed Gull among 100+ mixed gull flock, through a fence, around a puddle on the concrete ground right before Pier 94. Oh well... It was basically 6:00pm at that point and we were losing daylight quickly, with still some easy birds to get in the Presidio that Josiah had staked out. Thus began our long and very urban ride around the perimeter of the city. So funny biking in parks and quiet neighborhoods all day, to then be in the craziness that is the Financial District....quite the contrast, especially by bike.
We braved the headwinds and arrived at Crissy Field just before 7:00pm. Scanning for anything, but seeing nothing new. We made our way straight up to Ft. Scott, where we quickly saw Cliff Swallow, a very local breeder in the city (the last breeding spot?), and right after passed by some nearby palms where we heard our only weeping Hooded Oriole. We crossed over to the Presidio Hills where in some of the last light had a singing Wrentit, followed by a second one across the street. We killed a little time at the Lobos Dunes overlook hoping to hear a recently reported House Wren or maybe flyover Pine Siskin, to no avail. Finally, once it was properly dark, we rode down to Mountain Lake Park, where Josiah had received intel on a Great Horned Owl pair. The owls called right on cue, and even offered views in a what little light remained, being our last bird of the day, leading to our stokeness and the stokeness of the random passerby who happened to being walking right there and briefly saw one with us.
It was a tremendous day and a lot of fun! Our first time doing this route, which I think covered all the different habitats and timing between all the spots really well. Migrants have been slow to trickle in this spring, but many wintering birds have already left, which was definitely a challenge. But all things considered, we clearly chose a decently migranty day (WETA,BUOR, LAZB, BHGR), and happened to luck into a few of the remaining wintering birds (LISP, FOSP, HETH, WTSP). Another funny detail is that we did an SF Biking Big Day last year also on April 18th, where we only saw one more species than this year. Talk about consistent...
Big thanks to Josiah Clark for crafting this route and having that deep understanding of SF status & distribution, and to Jaime Chavez for the 3rd set of eyes and keeping the positive vibes going, even when his e-bike ran out of battery by the Embarcadero. Can't wait to do it again next year!
And thanks to anyone who made it this far in this lengthy post!
