Black-chinned Sparrows (Spizella atrogularis) are rarely found in winter much beyond their typical non-breeding range. Therefore, the Black-chinned Sparrow that spent the fall/winter of 2015-16 in Yolo County, California was remarkable. To put this record into perspective, I reviewed all available confirmed reports of extralimital winter Black-chinned Sparrows available from American Birds/North American Birds, Christmas Bird Counts, eBird, and various state rare bird committee reports. Based on these records, the Yolo wintering bird was the first found in winter in the Central Valley and the second winter record for Northern California. It was also the second most northerly winter record in California by 3.8° latitude (over 440 km) and further north than any winter record outside of California by over 3° latitude (over 330 km).
Ed Pandolfino (Thu,) studied this question.