I'm not sure how rare this is, but I have a set of mourning doves that made a nest in one of my daughter's outside toys:
http://i22.photobucket.com/albums/b...il222006046.jpg
I don't know where mourning doves usually nest, but I'm willing to bet that it isn't in the sink of a kitchen toy!
it looks a bit exposed, surprising it would choose somewhere so low down.