Juvenile Sabine's Gull in Costa del Este

Jan Axel Cubilla photographed this small gull in Costa del Este on Friday, November 20. The bird was noticeably smaller than the Laughing Gulls around it, with a thinner bill and a more delicate shape, plus it was browner on the hind neck and back and whiter below. Based on these differences (and on the white skirt of the secondaries and the black primaries) we are calling this a juvenile Sabine's Gull. If we squint we can even see the scaly back.