Our Crows Nesting?

Possibly my favourite birds here are the resident pair of Crows whcih until the last week or so were always foraging for food together, waddling through the long grass looking for stuff. For the last few days it has been a single Crow so I am assuming that the partner is sitting on a nest somewhere. Also on the Corvid front I am seeing Magpies regularly for the first time. There could well be Corvid trouble ahead....