#7 The size. This parameter depends entirely on the species to which the gull belongs.
#8 The color of the gull is contrasting.
Most often this is a white bottom. There are dark markings on the head and on the tips of the wings.
In some species, they are also present on the back as a disguise. Gulls have age differences in color: the older individual is predominantly white, but the young are brownish.
#9 Seagull feathers have such a quality as water resistance.
Nature has endowed them with this property so that the birds stay afloat and can hunt profitably.