Contra Costa county 1/22 Herring Run, East county local rarities, etc

Logan Kahle

Hi all,

Spent a great day with Dominik Mosur bouncing around some of my favorite Contra Costa county spots. We hit relatively few spots compared to my average visit, focusing more on thoroughly checking each spot we did hit. The morning started with low fog throughout the bayside, cleared on the bayside but was still overcast for the afternoon in East county.

We decided to mix up the route somewhat, skipping Pt. Isabel and Meeker Slough. We started at Vincent Park, checking the channel, harbor, and adjacent shoreline. Duck and diver numbers seemed low to me, but shorebird numbers more than made up for the dearth:
Red-throated Loon-1
Common Loon-1
Horned Grebe-20 was a nice count
Pelagic Cormorant-4
Black Oystercatcher-3
Black-bellied Plover-1
Long-billed Curlew-2
Marbled Godwit-4
Black Turnstone-50 was a good count in the county, but the flock unfortunately included no Ruddies
Sanderling-42 was a good count for the county
Least Sandpiper-8
"Thayer's" Iceland Gull-1 was mixed in with a large gull group of primarily Ring-billed and California at the lawn at dawn

Full eBird checklist here:

We proceeded to Canal Boulevard Viewing Platform for another look at the channel. Similarly small numbers of ducks, but many more birds were visible beyond Brook's Island. Highlights here included:

Brant-1 southbound flyby was my first in the county in a while
Red-breasted Merganser-1 was a good bird for here
Red-throated Loon-5 included 4 past brook's and 1 just 20 meters or so off the platform (!)
Black Oystercatcher-2
Black-bellied Plover-3
Long-billed Curlew-2
Marbled Godwit-2
Sanderling-120 was a very good count for the county
Least Sandpiper-15

Full eBird checklist here:

From there we headed to Point San Pablo where we spent a large amount of time exploring the various spots around the point. We started at the Ship Hull overlook where we witnessed a MASSIVE movements of Cormorants into the San Pablo Bay from across the bridge, presumably originating at the Chevron Pier Roost site. We estimated of 9000 Cormorants, which seems to likely be indicative of a HERRING RUN in this part of the bay just off San Quentin. The majority of the Cormorants were streaming to two different feeding sites, one off San Quentin and one just north of the Point San Pablo. While it was just attracting cormorants at this stage (so likely the fish haven't layed yet?) this may turn into a massive multi-family feeding frenzy in the next week, so stay tuned! Anyway, after the Ship Hull overlook we proceeded to the county park, where we spent a good amount of time checking the willows and adjacent areas on the immediate bayside. From there we headed to the pond and briefly checked around the edge. We then spent a good chunk of time walking around the oak ravines. We received one negative comment by a marina resident for parking in spot #3 as described in my Winter Wren post. By the time we got to the oaks activity had already dwindled significantly, and there was just a single main flock. Early morning appears to be best on this side of the peninsula. Anyway, highlights here included:

Surf Scoter-1500 was a good count here
Red-throated Loon-14
Pelagic Cormorant-30
Brandt's Cormorant-30
Double-crested Cormorant-6000 this was a great count of cormorants for the county, and the largest I know of
Cormorant sp-2500
Sharp-shinned Hawk-2
Red-breasted Nuthatch-4
Brown Creeper-1 at county park was my first for that site
ROCK WREN-1 continuing awesome find by Colin, hopping around cement blocks just before road turns near pond

Full eBird checklist here:

From there we blasted straight out to the bethel island area, briefly checking Summer Lake for any potential Boneparte's Gull concentrations. Highlights here included:

Boneparte's Gull-2
Forster's Tern-4

Full eBird checklist here:

From there we spent a large amount of time on Bethel Island. We started at Piper Slough, working through the ducks and searching for passerines. We then hit Willowest Marina, Frank's Tract overlook, and ended with an intensive search of the Golf Course in the middle of the island, an area I've never covered in the past. Passerine activity was quite high for the afternoon, and we found a nice assortment of ducks in the channel. Highlights included:
Cackling Goose-1 in with White-fronts was unusual to be perched on the island
Ring-necked Duck-2 were uncommon for the island
RED-BREASTED MERGANSER-1 female-type just off Piper Slough was rare in East county, and my first
Ruddy Duck-1080 was a nice count for the county
Ring-necked Pheasant-4 in the same spot as last time
Common Gallinule-2 on Franks Tract were a good bird for the island
American Coot-19000 constituting 9000 from Piper and 10000 from Frank's Tract was a good count
Black-necked Stilt-15
Least Sandpiper-8
Long-billed Dowitcher-6
Greater Yellowlegs-6
Lesser Yellowlegs-3
Mew Gull-1
Allen's Hummingbird-1 at traditional Willowest spot
Prairie Falcon-1 over golf course was a rarity for Bethel
HUTTON'S VIREO-1 photographed at Piper is the first documented record for East county
BROWN CREEPER-1 well-seen at willowest was the first record for this well-covered island, and one of few for east county
"Myrtle" Yellow-rumped Warbler-1

Full eBird checklist here:

We ended the day with a brief stop at Clifton Court, scanning from the parking lot. Northing exceptional was noted here, but a flock of at least 25,000 gulls stretched across the eastern shoreline of the forebay. For any larophiles out there, clifton court at dusk could be great in the next few evenings!

All in all it was a great day afield with 133 species noted.

Good birding,
Logan Kahle
San Francisco, CA

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