I'm also a newbie but noticed and bought from Dadant's (less than a buck) a
metal entrance reducer which just attaches to the front of the bottom super
with three small screws.  It provides an exit for the bees but the size of
the opening makes it impossible for a mouse to get in.  I've even heard of
mice chewing wider the small opening in the wooden entrance reducers and
still getting in but I'm sure their teeth don't work well on metal.
E. Geels (NW Iowa)

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
-- Visit www.honeybeeworld.com/BEE-L for rules, FAQ and  other info ---
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::