We were very fortunate to have this bird come down from the hillside and pose nearby. San Mateo County has fewer than 10 previous records of this species which ranges marginally into Bay Area foothills. This individual was found by Alvaro Jaramillo last Sunday, 31 May 2020. One or two Black-chinned Sparrows were seen at this location off and on between 6 June and 13 July 2018. I believe it is likely that this is one of the same birds returning. The uniform gray underparts without white on the belly is consistent with the subspecies S. a. caurina breeding locally in the eastern and southern parts of the San Francisco Bay area, but occasionally ranging further north and west. Its wintering range is unknown. These images were digiscoped with a Panasonic Lumix DMC-LX5 hand-held to a Nikon FieldScope III with a 30X WA lens. Voice recording: