Grey-headed Gulls Chroicocephalus cirrocephalus foraging in spillway turbulence at Gariep Dam, South Africa

Abstract

On 8 March 2026 several Grey-headed Gulls Chroicocephalus cirrocephalus were observed foraging over the turbulent outflow below the Gariep Dam wall, during a period of strong overflow. The birds repeatedly flew low over the torrent and frequently entered the dense spray plume immediately below the falling sheet of water. Swifts and swallows were also actively foraging over the same area. The observation suggests opportunistic feeding associated with prey concentrations created by intense hydraulic turbulence below the spillway.