FG: Mommy, a bird just flew out of our bush!
Me: Where did it go?
Robotson: It's in the tree, but you can't see it.
Me: Why not?
Robotson: It's camouflaged.
Dimples: See! Song! Pop pop!
Me: Why would it be hard to see?
Robotson: So nothing will eat it.
FG: We don't eat birds. Mommy, I don't want anyone to eat the bird!
Dimples: POP POP!
Me: Why doesn't it want to be eaten?
Robotson: Be-Cu-uz MOM, then it couldn't have babies and keep living.
Me: Oh, I didn't know that.
Robotson: Duh, Mom. That's evolution.
O.k. not exactly evolution, but still a fun conversation to have.