I was told & believed for years that when you heard "cuckoo" it was 2 birds - one saying "cuck" + one saying "coo"!
A childhood belief about birds

others believed things like this
- when I was little I was afraid of flies until mom told me they were baby birds!— Lisa
- My dad told me that the reason Birds didn't get electrocuted on overhead wire was they had rubber feet!!— Derricki
- My dad told me that kiwi fruits were kiwi birds testicles. They are the right shape and kind of furry— jefnier
- My Grandmother once told me she could unscrew her feet. I believed that for years.— Andy Bettison
- I used to believe that gum was made outta pig fat becuase of what my dad told me. I believed him for years.— Maddy
- My father told me that Spam was a mix of sparrow and ham. I believed this for years lol— Tara the Terror