The black-legged kittiwake (Rissa tridactyla) is a seabird species in the gull family Laridae.
The English name is derived from its call, a shrill ‘kittee-wa-aaake, kitte-wa-aaake’. The genus name Rissa is from the Icelandic name rita for this bird, and the specific tridactyla is from Ancient Greek tridaktulos, “three-toed”, from tri-, “three-” and daktulos, “toe”.
It has a white head and body, grey back, grey wings tipped solid black, black legs and a yellow bill. Occasional individuals have pinky-grey to reddish legs, inviting confusion with red-legged kittiwake. The inside of their mouth is also a characteristic feature of the species due to its rich red colour. Such red pigmentation is due to carotenoids pigments and vitamin A which have to be acquired through their diet.