Ahhh hahaha this is great.
My brother has the old style mailbox attached to his house (about the shape and size of a ream of paper), I got his mail for him and discovered a birds nest in the bottom. Now abandoned.
I have some hanging plants that Wrens sleep in, they are at about head level, so just about anytime I accidently bump one at night, an angry wren comes flapping out scaring me half to death.