Who owns the copyright on my checking account?

Let’s say I wrote ten checks a month. I don’t, but that’s another story And on each check I write a couple of original lines of verse. Someone at the bank sees these and publishes them herself.

Who owns the copyright to my checks?

- me, because I wrote the verse on the check?
– the check printer, because I wrote the verse on patterned paper that they created?
– the bank, because they processed the checks on my account at their bank?