More Mice than Men

My mice problem has not been solved yet! I discovered that the mice have a nest more or less directly under the alabaster vase  which I have made into a lamp, and above the radiator inside the window ledge. The entrance is from the window box in the left corner as seen. Inside there is a small gap between the marble facing and the brickwork through which the mice could come, but the droppings do. Additionally the mice have an underground nest in the window box! I placed all my traps therefore outside in the window box. Three in all, two death traps and one live trap.

In this picture you can see that I caught two mice the other day, one in the death trap and one in the live trap. The bait I used was mainly Nutella. The dead mouse's tail is nicely visible in the left of the picture.

This lucky little chap I took to show Christopher Thomas my 3 year old grandson and then we both took it and set it free in the woods near where we saw some rabbits, so he would not be alone!

This evening I have caught another mouse in one of my death traps, and there are clearly more out there. When I trapped the first two I got my landlord to come and see and so he is now arranging for all the holes to be filled in.

The big question still remains, how and why did the mice climb up to the fourth floor window box? Once the holes in the masonry are plugged will I have to dig up the window box to get rid of the rest of them?

I'd be grateful for all advice received.

Since writing this this morning I have discovered a dead mouse on my balcony!! Surely this can't go on?

Number six! How many more are out there? It was caught this evening 3 March in my window box on the 4th floor???? 

Today 6 March. Number 7! I think I need a cat.

Just discovered number 8 was caught by the trap I set up right outside the hole they have dug in my window box. I seem to be doing quite well without a cat now.