Wood Sandpiper ©Josh Greenfield
September is well-known among birders as the heart of fall migration, with many species dispersing and embarking on long migrations to their wintering grounds. With all this bird movement, it’s inevitable that some individuals get lost on their journeys and turn up as “vagrants” well out of their normal range. Birds are everywhere in September, and it can feel as though anything is possible at any given moment. This September in Yolo County was no exception.
The indisputable highlight was a WOOD SANDPIPER found at the Woodland Wastewater Treatment Plant (WWTP) on 9/9 (JG). This mega-rarity is a small member of the genus Tringa (which includes local species such as Greater and Lesser Yellowlegs), and is native to Eurasia. One can imagine the shock local birders felt when news of this bird came across local communication forums. A wild chase ensued, yet the bird had disappeared before people arrived. Thankfully, the bird was eventually relocated at a different pond nearby, where it remained for a day and a half. It was seen by dozens of birders from Yolo County and beyond, and was photographed by many. This will represent the fifth record for the state of California and is a first for Yolo County!
Yolo County’s impressive songbird migration often draws many birders to the region, as riparian habitats such as Putah Creek attract warblers, flycatchers, tanagers, and the like. This year an impressive string of vagrant eastern warblers were discovered in the county. A NORTHERN PARULA kicked things off as a one-day-wonder at Elkhorn Regional Park on 9/5 (ZP, JJ). A few days later on 9/10, a hatch-year TENNESSEE WARBLER was photographed at Grasslands Regional Park (SSm). This bird disappeared shortly after its initial observation, but fear not, as two more TENNESSEE WARBLERS were found within the next week! Both were at the Putah Creek Riparian Reserve, with the first being a hatch-year reported first on 9/15 (HH), and the second an adult male photographed on 9/18 (SA, JH, JJ). A NORTHERN WATERTHRUSH put on a show for many birders as it bobbed around the muddy embankment of the Putah Creek Riparian Reserve from 9/15 to 9/18 (SSc). A striking hatch-year CHESTNUT-SIDED WARBLER at Fishing Access #1 in Putah Creek Canyon was the first in the county since 2022, and was successfully chased for three days (ZP, JJ, EM). In addition to the warblers, a male SUMMER TANAGER was well-described from the Wild Wings subdivision along Cache Creek on 9/19 (eBird).
The notable songbird records did not stop at the eastern vagrants. Two CHESTNUT-BACKED CHICKADEES were found during the month, presumably dispersants from a breeding population in the Coast Ranges. The first was photographed at Putah Creek Fishing Access #3 on 9/6 (ZP, JJ, CT), and the second was seen by a few at Putah Creek Riparian Reserve on 9/18 (LH). A BLACK-THROATED SPARROW visited Uslan Farms near Clarksburg for six days beginning 9/7 (TU). This juvenile is only the seventh record for the county. More expected was a GREEN-TAILED TOWHEE along Fiske Creek Road above Rayhouse Road on 9/23 (JG). Also of note was a SAGE THRASHER seen briefly at the Cache Creek Preserve on 9/26 (CD).
September 2023 will be remembered for its crazy incursion of SABINE’S GULLS across inland California, with dozens of records from around the state including multiple in the Central Valley. Usually a pelagic species, occasionally SABINE’S GULLS will wander in the fall, though they are not common inland away from large reservoirs. Yet this year Yolo County was fortunate enough to get not one, not two, but three Sabine’s Gulls during the period, all of them immatures at WWTP. The first individual, found on 9/21, was the first in the county since 2017 (EI). This individual was only present for about two hours before birders watched it pick up and circle higher and higher, drifting on thermals like a terrestrial raptor before flying out of sight. While disappointing for those who were not able to make it out in time, redemption was sweet a week later when another SABINE’S GULL was found at Woodland WTP on 9/26 (JG). It was joined by a second individual a day later (KS) and both individuals continued until 10/1.
In addition to the SABINE’S GULLS, two FRANKLIN’S GULLS were observed during the period at WWTP. The first was a crispy juvenile beginning 9/12 (ZP, JJ, EI), and the second was an adult reported on 9/30 (MP). Sticking with waterbirds, a RUFF visited a few flooded fields north of Knights Landing on 9/4 (JG), where it was seen by a few. Six SNOWY PLOVERS were found together at the Yolo Bypass Wildlife Area on 9/1, representing both an abnormally high tally and a late record for the species (ZP, JJ).
A GRASSHOPPER SPARROW was an unexpected find near Winters Wastewater Treatment Plant on 9/20 (JG). Typically this species is only detected as breeders in the spring, so this report of a fall migrant was surprising. Finally, two LESSER NIGHTHAWKS flew over a private residence near Cache Creek in Guinda on 9/25 (ES). While not entirely out of season, this is a late date for the species and may represent migrating individuals as opposed to local breeders.
Thanks to the following for their reports:
Anonymous eBirder (eBird), Cameron Tescher (CT), Chris Dunford (CD), Elliot Schoenig (ES), Emmett Iverson (EI), Ethan Matsuyama (EM), Harrison Horn (HH), Jim Holmes (JH), Josh Greenfield (JG), Julian Johnson (JJ), Kirk Swenson (KS), Liam Huber (LH), Michael Perrone (MP), Sam Schmidt (SSc), Sean Smith (SSm), Steve Abbott (SA), Tom Uslan (TU), Zane Pickus (ZP)
Photos and Audio Recordings:
Wood Sandpiper: https://ebird.org/checklist/S194649921
Tennessee Warbler (Grasslands Regional Park): https://ebird.org/checklist/S194649274
Tennessee Warbler (Putah Creek, hatch-year): https://ebird.org/checklist/S195612200
Tennessee Warbler (Putah Creek, adult male): https://ebird.org/checklist/S195643600
Northern Waterthrush: https://ebird.org/checklist/S195301315
Chestnut-sided Warbler: https://ebird.org/checklist/S195642703
Chestnut-backed Chickadee: https://ebird.org/checklist/S194181997
Sabine’s Gull (9/21): https://ebird.org/checklist/S195990825
Sabine’s Gull (two birds): https://ebird.org/checklist/S196829969
Franklin’s Gull: https://ebird.org/checklist/S194952066
Ruff: https://ebird.org/checklist/S193994152
Snowy Plovers: https://ebird.org/checklist/S193774241
Grasshopper Sparrow: https://ebird.org/checklist/S195857098
–Zane Pickus