The mockingbird was sitting on our fence, but seemed to be posing as a hawk. LOL! I've never heard these sound like a hawk, but they do mimic the sounds of seagulls and crows sometimes.
Good shot- he's surely exuding the attitude of one! The Blue Jays here mimic the Red Shoulder Hawks all the time so I imagine a Mocking Bird could in effect mimic them too if they wanted to.