Pheasant - nest in open field?

As I was driving home today from work I saw a very strange scene

There was a cock pheasant and a female around a pile of twigs (nest like) in an open field.  The female admittedly wasn't sitting on the nest but just by it, whilst the male a couple of feet away.  The site of the "nest" which was quite large was only about 6 feet into the field from the road.  It was definitely a nest, the twigs taken from the stubble field it was laying on was too neat to be just a pile that was windblown.  Other than seeing pheasants in the hedgerow, fields and flying in front of my car, I admit I don't know anything about their nesting habits but surely this must have been a mistake! wrong season for a start! I have checked the RSPB site but there isn't anything on there about their nesting habitats. Anyone have any ideas?