It's a Poem! It's a Riddle! It's two, two, two mints in one! Depending on your perspective, I'm getting better (or worse) at devising bad riddles. Give this one a good think... it might come to you. Good luck:

Bat guarded my City;
I'm also a Ram.
My ball summons ducks
Can you guess what I am?

Here is the ANSWER.

THE ANSWER:

DODGE.

Bat Masterson lived in Dodge City, Kansas, where he served as Ford County sheriff.
The Ram is the symbol of the Dodge automobile line.
The heaving of a dodge ball would summon "ducks" from those trying to avoid being hit.