Slender-billed Gull is mostly white except pale-grey mantle and black tips of primaries (outer border of 2 secondary is black too). Belly and flanks have very light pinkish tinge. Bill and legs are dark-red. Eyes are whitish, yellowish or reddish; eyelids are red. Juveniles are very similar to juveniles of Black-headed Gull; upperparts are grayish with buffy edges of feathers, tail feathers are with black tips, flight feathers have much of black; bill and legs are orange. Sizes: wing 280 - 330 mm, tarsus 45 - 55 mm, bill 35 - 46 mm. Weight: 271-320 gram.
"Птицы Казахстана" том 2. Алма-Ата, 1962.
