Black-headed Gull Black-headed Gull, Prague, Czechia, October 7, 2024Canon EOS R5 with Canon 100-500 mm L-series lens; 500 mm; ISO-320; f/7.1; 1/800 sec. This page is for the Black-headed Gull (Chroicocephalus ridibundus). Black-headed Gull, Prague, Czechia, October 7, 2024Canon EOS R5 with Canon 100-500 mm L-series lens; 500 mm; ISO-1000; f/8; 1/800 sec. Black-headed Gull, Prague, Czechia, October 7, 2024Canon EOS R5 with Canon 100-500 mm L-series lens; 500 mm; ISO-1000; f/8; 1/800 sec.