Golden-crowned Sparrow (Zonotrichia atricapilla) at Portola Valley Ranch
ID confirmed by Charlie Quinn, Bob Dodge, Garth Harwood, Dudley Carlson. Garth Harwood (HV): Note the 'gold' patch just above the bill. Golden-crowned, for sure. Dudley Carlson: Not a towhee, and I'm pretty sure this is a Golden-crowned sparrow. No other one has exactly that combo of gold between the prominent dark crown lines, plus dark line behind eye.