you can try to make a little house not to big, an then you wanna place 2 doors; 1 at the right side and 1 at the left side, also dont forget the floor. Then simple as this: you lure it to your house, and then you jump on to your roof, and also dont forget to open the door on the side you found the shrew so you could lure him into your house. And then if you didn't forget to open the door the shrew should walk in to your house. Then quick jump down walk in and close the door. The shrew can now not dig down and you could do whatever you want to do with it.