(c) Nick Truby
Jeff Pursey very kindly alerted the wider birding community to its presence this afternoon.
Apparently first seen and identified yesterday at the Bicester Wetlands reserve.
Note that as it's quite close to the road it does tend to flush rather easily but seems to return to the same spot so best viewed from your car.
All above pictures courtesey of Nick Truby
Video (c) Gnome