What to do about pigeons pooping on my path?

A group of pigeons have taken to roosting on the pipes just above our side gate. I wouldn't mind except for one problem... Each morning and evening, at the start and end of each commute, we find ourselves unavoidably wheeling our bikes over a thick, slippery layer of guano that sticks to our tires and shoes.

Is it time to introduce avian hostile architecture (i.e. bird spikes) or is there a more peaceful, cooperative solution to my dispute with my feathered neighbours?