Late winter is a unique time of year in Yolo County, as winter birds begin to clear out but spring migrants are yet to arrive. Significant rains this season kept water levels high, and gull numbers around the Yolo County Central Landfill swelled into the thousands. This provided the setup for some of the best local gulling in recent memory, and the highlights of February were dominated by an impressive list of rare gulls.
The flooded “Borrow Pits” west of County Road 104 by the landfill proved to be the best spot to study gulls this year, giving those up for the challenge the ability to look through thousands of individuals in the hopes of finding rare species. An adult WESTERN GULL, presumably a female based on its small size, was found here on 2/2 (EM, CD). It remained for over a week and was later joined by a second adult on 2/4 (EM, FF, ZP). Western Gulls are common along the coast but rarely stray inland. However, February may be the best time to find them as they migrate and occasionally come through Yolo County.
The continuing first-cycle GLAUCOUS GULL continued to be seen by many, and on 2/3 it was joined by another immature, which appeared to be a second-cycle (ZP). Two immature Glaucous Gulls were viewed simultaneously on 2/17 (EM, ZP, ES, KF), so it is unclear how many immatures were moving around the area. For some reason, adult Glaucous Gulls are much more rare in the county than immatures, so an adult at the Borrow Pits on 2/10 was a special treat (KS, EM, ZP, KF, ES). A late second-cycle LESSER BLACK-BACKED GULL found on 2/7, and was briefly seen again a week later before disappearing (EM, FF, ZP). Finally, a potential immature SLATY-BACKED GULL was photographed on multiple occasions in early February (EM), but unfortunately a definitive identification could not be reached. Experts with this Asian species were very intrigued but ultimately the identification was left as probable. Yolo County has just three prior confirmed records of Slaty-backed Gull, the last of which comes from February of 2020.
While the gulls dominated the show, a sprinkling of other rarities brightened the month. Two different SWAMP SPARROWS were found in February, and both proved quite chaseable to those with patience. The first was discovered on 2/4 at Bridgeway Island Pond in West Sacramento (DM), and continued to be seen for a couple of weeks. The second, at North Area Drainage Pond in North Davis, was first photographed on 2/18 and has since been enjoyed by many (JG). A pair of EVENING GROSBEAKS were heard as they flew over West Davis on 2/5 (TH). They were identified by their call to be Type 1, which is the subspecies from the Pacific Northwest. Dozens of other Type 1 Evening Grosbeaks were reported in neighboring counties during the month, suggesting a small irruption of the subspecies into the Central Valley.
A crisply-plumaged PLUMBEOUS VIREO was found on the main quad of the UC Davis campus on 2/7 (KD). This bird was often difficult to track down, but it rewarded those who chased it early in the morning before the masses of students arrived. This Rocky Mountain-counterpart to the Cassin’s Vireo is a tough bird to see in the county, with this being the first widely-chasable bird in the past few years. Unusual in winter was a HAMMOND’S FLYCATCHER in Woodland beginning 2/8 (AS). Regular in migration, this species has only a few winter records. An apparent female COMMON GOLDENEYE x BUFFLEHEAD hybrid was at Davis WTP on 2/5 (KS). Somewhat incredibly, this was the second individual of this hybrid combination to be in the county at the same time, with a male still present in West Sacramento.
A brilliant male YELLOW-BELLIED SAPSUCKER was photographed on private property in the Capay Valley on 2/27 (MS). Coincidentally this represents the second Yellow-bellied Sapsucker in the county this winter, as another male continued along the Sacramento River at the Elkhorn FIre Station.
Finally, other continuing birds included the LONG-EARED OWLS in residential Davis, the GREATER ROADRUNNER at a winery in the Capay Valley, and the WINTER WREN in Putah Creek Canyon.
Thanks to the following for their reports:
Alex Single (AS), Chris Dunford (CD), Daniel Murphy (DM), Elliot Schoenig (ES), Ethan Monk (EM), Frank Fabbro (FF), Josh Greenfield (JG), Ken Ferguson (KF), Kirk Swenson (KS), Konshau Duman (KD), Mark Sawyer (MS), Tom Hahn (TM), Zane Pickus (ZP)
Photos and Audio Recordings:
Western Gull (adult #1): https://ebird.org/checklist/S127731635
Western Gull (adult #2): https://ebird.org/checklist/S127727334
Glaucous Gull (immature): https://ebird.org/checklist/S128357949
Glaucous Gull (adult): https://ebird.org/checklist/S128037317
Lesser Black-backed Gull: https://ebird.org/checklist/S127890978
Swamp Sparrow (Bridgeway Island Pond): https://ebird.org/checklist/S127608135
Swamp Sparrow (North Area Drainage Pond): https://ebird.org/checklist/S128789856
Plumbeous Vireo: https://ebird.org/checklist/S128181760
Hammond’s Flycatcher: https://ebird.org/checklist/S127904536
Common Goldeneye x Bufflehead (Davis WTP): https://ebird.org/checklist/S127714205
Yellow-bellied Sapsucker (Capay Valley): https://ebird.org/checklist/S129799760
Plumbeous Vireo
Photo by Kirk Swenson
–Zane Pickus