Rats in trailer

Hello Larry,   Can you attempt an ID for me, please?  I live in a rural, wooded are of PEI. There are farm fields nearby. There are no derelict buildings, garbage dumps, or refuse/compost piles anywhere. I have a new shed, which is clean and used for storage, and a Boler trailer.   There were two nests in two of my storage compartments inside the trailer. There were mouse droppings, but in one nest area, larger droppings as well. I think, not the 1/2″ or 3/4″ length.  UNDER the Boler was a tunnel entrance, clean and perfectly round, about 3″-3-1/2″ wide. I poured almost a gallon of water down this.  There was a VERY strong stink, similar to mouse pee but MUCH stronger, both inside where the nests were, and near the tunnel. The stink was also in my shed, where some rodent had squeezed under a loose plastic bin lid and eaten seeds and defecated. Do you think this was a rat of some sort?   My coworker says chipmunks live in ground tunnels on PEI…..  I’ve never heard of that. It may have been squirrels or chipmunks inside the Boler, but what about the tunnel? I saw another tunnel near my  neighbour’s cottage, too. If there are rats, I will poison them. Thank you for any opinion you can give. Sincerely, Sunny

Without photos it is difficult to identify your pest problem, but your description indicates you likely have Norway rats.  They like to burrow.   the burrows always include an escape route, just in case someone pours water down the main entrance. You should find the entrance hole into the trailer and plug it.  Set some traps inside to catch any that may be inside and also 2 or 3 traps near the tunnel entrance. Poison may result in a bigger problem.  Dead rats can be worse than live ones if they die in an inaccessible cavity.  Read more about rodent control: http://pestcontrolcanada.com/how-to-get-rid-of-rodents/