Had a friend who owned a greenhouse and found that he could control the birds that kept getting inside and the mice by soaking bird seed in ethylene glycol (auto antifreeze) and spreading it around.
After 1 week no birds and no mice..
Since I don't want to kill any birds, I'd just gut a hole big enough for a mouse to get into a coffee can and put the lid on after putting a couple of teaspoons full of soaked seeds in there.. They will carry the seeds back to their nest..
We don't stop playing because we get old, we get old because we stop playing... :)