Circus sighting

Collingham tonight produced a few bits and pieces - a Cuckoo calling somewhere off to the north, at least 17 Yellow Wags (13 of them on Carlton Ferry Farm Pit), 2 Green Sands, and a female-type Marsh Harrier - the second in 10 days; or the same bird hanging around? It was flying north when I picked it up, but it then turned south over Mons Pool (encouraged to do so by a party of corvids), then making a beeline in the direction of Langford (where apparently there aren't any breeding birds this year).