Sarah,

I used to live in Orange County and had a similar bird in the neighborhood. It was uncanny how well it could imitate a car alarm:

whoOOOp-whoOOOp-whoOOOp-whoOOOp eRRRnh-eRRRnh-eRRRnh-eRRRnh bEEdup-bEEdup-bEEdup-bEEdup whoOOOp-whoOOOp-whoOOOp-whoOOOp

It was the exact same pattern as our neighbor's alarm (which went off frequently) and the bird had it down pat.

I suppose the little guy was trying to attract the ladies SoCal-style.

Anne