I have just Velcroed some old DVDs, one on each side of my helmet. The logic is that the strange reflections coming off a CD or DVD surface play havoc with the eyesight of the attacking bird. This is the same logic as bird repellent type which has the same confusing patterns.
I was attacked last year at about this time (it drew blood), so I am pretty keen to avoid a repeat.
Has anyone else tried this?