From the size and length of the tail my guess is rat. Voles have short tails.
That was my thought, too. I did not see a tail, but if it has a pretty long tail, I would say it is definitely a rat. Rats are unwanted vermin, but they are nevertheless very intelligent animals. I would use traps before I used poison. You are asking for all sorts of problems if you use poison. Do not do it.
