In terms of size I think this bird is slightly larger than the pne in photot. Also considering that it is the central valley of California where this bird was seen ( hence the altitude is not above 100 ft, the most likely answer would still be the mocking bird. The yards and skies are full of them this time of year, particularly in the central valley of california
The mocking birds I’ve seen in CA were black with white wingtips ....or white with black wingtips. They’d sit on phone poles and sometimes just jump straight up in the air and then down again for apparently no reason ....