"Liaoyang Science Popularization" red-billed giant gull: Winter feathers and summer feathers are roughly similar

The red-billed giant gull is a large water bird with a body length of 47 to 55 cm. Summer feathers are black on the forehead, crown, pillow and crown feathers. The hind neck , tail coverts and tail are white , and the tail is forked. The coverts on the back, shoulders and wings are silver-grey. The first eye and the side of the head below the eye and ear feathers are white; the chin, throat and entire lower body are also white. Winter feathers and summer feathers are roughly similar, but the forehead and top of the head are white with black longitudinal stripes. Some heads are all white, with only black spots in the ear area. The upper body is lighter.

Red-billed gulls inhabit coastal sands, flat mud, islands and coastal swamps. They often nest in small groups, and rarely nest in pairs alone. The eggs are ochre, greenish-white, ochre-white or pale brown in color and are covered with hazel or black spots.

Size measurement: weight male 560 to 656 g, female 520 to 640 g; body length male 505 to 540 mm, female 502 to 545 mm; mouth peak male 63 to 73 mm, female 66 to 77 mm; wing male 387 to 425 mm, female 400 to 430 mm; tail 134 to 150 mm; tarsal 38 to 47 mm.

Source: Dandong Forestry and Grassland Development Service Center