Nick Maclaren wrote:

We were away from our house for a couple of months,
and when we came back there were hundreds of mouse (or rat) droppings
in just 2 rooms.
To get into one of the rooms, the mice had to climb up a 2 metre wall.
They got into the other room through an air-hole.

Yes. Metal flashing (ideally not lead - it's too soft). Either
4" flush and vertical or 2" sticking out and down.

Thanks for the suggestion - can one get special vertical metal flashing?
I've never seen it in use - how is it attached to the wall?

Also, is there anything better than mice traps to dissuade them?
They came through a garden, and I wouldn't like to put anything down
that could harm other animals.

Poison. Put it inside the house.

Actually the mice climb onto a balcony before getting into the room.
I'll try putting down poison there.


--
Timothy Murphy
gayleard /at/ eircom.net
School of Mathematics, Trinity College, Dublin