I have successfully fought the bird wars for years using one of those plastic owls sold in hardware or garden stores. just set it on you hood at night and the birds will stay away. It’s amazing - you can walk outside with one in a paper bag, take off the bag, and yard gets quiet.
Put double-sided thick foam sticky tape on top of the truck’s mirrors. I think birds will respond same as cats, they don’t like sticky stuff on their feet.
i would bet it is a red cardiinal, at least it was for me. the first year it was cute. year two it was getting to be a nusinse. the third year, i shot the dam bird with 22 bird shot. The bird either thinks it has found a mate or a competitor and once it sees itself it will stay there all day and attack the little birdie in the window.
That bird shot’s kinda hard on mirrors isn’t it? 
Rubber snakes from the dollar store should do the trick. Just drape them on the side mirrors. Since birds can see color try and find fairly realistic ones.