We had a major mouse problem at my house a year or so ago. I have birds too, so there was always seed and stuff on the ground, even if I vacuumed a couple times a day (which obviously isn’t always possible since I am not always home!).
For me, things got serious when I found mouse poo in my bird’s cages. EWW! Not to mention they can be dangerous, especially to a tiny bird! I ended up putting Riley (the rabbit) in a small cage that I could place up off the ground so that the mice couldn’t get to it, and then placing traps all over the house. Sadly we had crazy smart mice (we watched them physically jump over the traps to avoid them, despite yummy peanut butter and cheese!), so we eventually had to resort to poison, in order to keep my babies safe. I hated doing it (I don’t even like snap traps), but my feathered and furry baby’s health had to come first!
After we had the problem under control, my Mom looked into getting an exterminator out to the house to go around the outside of the house and find the little cracks and holes the mice can get into to hopefully prevent them getting in in the future. They can get in tiny holes you can’t even see. We haven’t had a problem since, but I also moved out with the animals, which I think were a major attractant to the mice.