Grey Heron - Black-headed Gulls interaction

From the walk to Cockshoot Broad Dave and I watched as a Grey Heron landed on a roof on the other side of the river (Horning).  Successive Black-headed Gulls swooped by calling and each time the heron craned up to look and squawked back at them.  Went on for several minutes before the heron flew off.

Grey Heron and Black-headed Gulls, Horning, 21st February