An elderly lady buys a pair of parrots, but cannot identify their sexes.

She calls the shop, and the man there advises her to watch them carefully and
all would become clear in time. She spends weeks staring at the cage and
eventually catches them doing what comes naturally. To make sure she doesn't
get them mixed up gain, she cuts out a ring from a piece of cardboard and
puts it round the male parrot's neck.

A while later, the local priest visits the old lady. The male parrot takes
one look at the father's collar, wolf whistles, and says,

"I see she caught YOU at it, too...."