Two Bitterns showed today at Marazion Marsh, both around midday. I was only expecting flight shots as these birds seem to take short sorties from one area to another. The lower bird surprised me though as it appeared out of the reeds directly in front of the roadside viewing platform, and stayed there for about a minute in full view.
Text edited and updated 31st Jan: This winter has been one of the best for Bitterns in Cornwall. The full numbers present will become evident but at Marazion Marsh, up to five have been present (31st Jan), at Loe Pool, a minimum of two, probably four, one at Rospannel, one at Stithians, one at Par Beach pool, one at Porth Reservoir (31st Jan) and one at Swanpool are the records that I'm aware of. Undoubtedly more are lurking undetected.
The images were taken with the 300mm F/2.8 lens and new TC3 aspherical 2x teleconverter, which seems to work well with this lens, but struggled to find focus with the 600mm!