Much to the bewilderment of the French, the English won a major upset and they began mocking the French by waving their middle fingers at the defeated French, saying, See, we can still pluck yew! Since ‘pluck yew’ is rather difficult to say, the difficult consonant cluster at the beginning has gradually changed to a labiodental fricative ‘F’, and thus the words often used in conjunction with the one-finger-salute! It is also because of the pheasant feathers on the arrows used with the longbow that the symbolic gesture is known as ‘giving the bird.’
And yew thought yew knew every plucking thing.
When I read this I thought ‘wow what a fantastic story!’. But then I thought I would check it with Snopes, and alas it is not true. But as always, Snopes gives a nice explanation. So if you see this floating around the internet you can loftily say ‘nope, not true. And you know why?’