September: the best month of the year for rare birds in California and the month that every birder eagerly awaits. It was peak fall migration which often brings out-of-range visitors as birds freshly hatched in the far northern hemisphere find their way south for the first time. As usual for September in Yolo County, Putah Creek took center stage with a smattering of eastern vagrant warblers.
Although Yolo had eight individual eastern warblers they were all either Chestnut-sided, Blackpoll or Tennessee Warblers. It kicked off with a Chestnut-sided Warbler at Putah Creek–Levee Road (AF, SB) on September 11th. This started the “Patagonia picnic table effect”, which is when birders chasing a rarity find other good birds due to increased coverage. A Blackpoll Warbler was found the next day (RM) and the second of four Tennessee Warblers were found (LP), both at Levee Road. The first Tennessee Warbler was found the previous day in a backyard in North Davis (AK).
A different Chestnut-sided Warbler was found along Putah at Fishing Access #3 (SS) on September 18th. That same day a Tennessee Warbler was found on the Yolo side of the Sacramento River at Elkhorn Slough (BW). The following day, September 19th, another Tennessee Warbler was found along Putah just west of Stevenson’s Bridge (BW). Yolo’s second Blackpoll Warbler of the fall was found at Babel Slough on the 17th (MP, SH, EI, BW) and a Green-tailed Towhee was spotted along Babel Slough (MM, LC) on September 19th.
Biologists doing surveys on private property in southern Yolo county had a Stilt Sandpiper; this bird stuck around from September 14th-21st (KD, LW). Earlier in the month a single Type-2 Red Crossbill flew over the UCD campus (AE).
Also of note was the first September record of Eurasian Wigeon for Yolo County, this sets the earliest arrival date for this species in the county (JL, EI). This bird was found on September 23rd at the North Regional Pond in Woodland.
Thanks to the following for their reports: Andrew Ford (AF), Sarah Barsness (SB), Roger Muskat (RM), Linda Pittman (LP), Alison Kent (AK), Sean Smith (SS), Bart Wickel (BW), Michael Perrone (MP), Steve Hampton (SH), Emmett Iverson (EI), Mark Martucci (MM), Lyann Comrack (LC), Konshau Duman (KD), Lynette Williams (LW), Andy Engilis (AE) and Jeri Langham (JL)
eBird checklists:
Chestnut-sided Warbler at Levee Rd: https://ebird.org/checklist/S94515867
Chestnut-sided Warbler at Fishing Access #3: https://ebird.org/checklist/S94515867
Blackpoll Warbler at Levee Rd: https://ebird.org/checklist/S94616142
Tennessee Warbler at Elkhorn Slough: https://ebird.org/checklist/S94830335
Compiled by Emmet Iverson, Davis, CA