The Truth Behind 10 Common Superstitions
8. Counting Magpies
An old fashioned superstition associated with the UK in particular centres around the magpie.
It is believed that when you see a lone magpie, you should then inquire “Good Morning, Mr Magpie, where is your wife?”. This goes hand in hand with the old nursery rhyme the describes the varies meanings and portents of different numbers of magpies ("One for sorrow, two for joy..." et cetera).
These could be explained by the fact that magpies are monogamous and mate for life, meaning that to see a lone magpie is actually pretty uncommon (there are also all sorts of implications about luck and omens in love).
The game could also have been a way of teaching children manners by way of them learning to enquire after a person's relatives when they meet them.