Black-legged kittiwake

Black-legged kittiwake
File:Rissa tridactyla (Vardø, 2012).jpg
File:Kittiwake (Rissa tridactyla) (W1CDR0001389 BD30).ogg Calls, recorded on Skomer
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Charadriiformes
Family:	Laridae
Genus:	Rissa
Species:	R. tridactyla
Binomial name
Rissa tridactyla (Linnaeus, 1758)
File:Rissa tridactyla area all.PNG
Summer      Winter

The black-legged kittiwake (Rissa tridactyla) is a seabird species in the gull family Laridae.

This species was first described by Linnaeus in his Systema naturae in 1758 as Larus tridactylus.

File:Rissa tridactyla MWNH 0344.JPG

Eggs, Collection Museum Wiesbaden

In North America, this species is known as the black-legged kittiwake to differentiate it from the red-legged kittiwake, but in Europe, where it is the only member of the genus, it is often known just as kittiwake.

The adult is 37–41 cm (15–16 in) in length with a wingspan of 91–105 cm (36–41 in) and a body mass of 305–525 g (10.8–18.5 oz). It has a white head and body, grey back, grey wings tipped solid black, and have black legs and a yellow bill. Occasional individuals have pinky-grey to reddish legs, inviting confusion with red-legged kittiwake. In winter, this species acquires a dark grey smudge behind the eye and a grey hind-neck collar. The name is derived from its call, a shrill 'kittee-wa-aaake, kitte-wa-aaake'.

It is a coastal breeding bird around the north Pacific and north Atlantic oceans, found most commonly in North America and Europe. It breeds in large colonies on cliffs and is very noisy on the breeding ground. Cliff nesting for gulls occurs only in the Rissa species, and the kittiwake is capable of utilizing the very sheerest of vertical cliffs, as is evident in their nesting sites on Staple Island in the outer Farne Islands (Hogan, 2005). One to two buff spotted eggs are laid in the nest lined with moss or seaweed. The downy young of kittiwakes are white, since they have no need of camouflage from predators, and do not wander from the nest like Larus gulls for obvious safety reasons.

At fledging, the juveniles differ from the adults in having a black 'W' band across the length of the wings and whiter secondary and primary feathers behind the black 'W', a black hind-neck collar and a black terminal band on the tail. The old fisherman's name of "tarrock" for juvenile kittiwakes is still occasionally used.

They are fish feeders, and are more pelagic than Larus gulls outside the breeding season. They do not scavenge at tips like some other gull species.

There are two races of black-legged kittiwake:

• Rissa tridactyla tridactyla – (Linnaeus, 1758) in the North Atlantic Ocean, which is unique among the Laridae in having only a very small or even no hind toe.
• Rissa tridactyla pollicaris – (Ridgway, 1884) in the north Pacific Ocean, which (as the name pollex, thumb, suggests) has a normally developed hind toe.

Gallery

• Black-legged-Kittiwake.jpg

  In flight, Heligoland, Germany

• Black-legged Kittiwake RWD2.jpg

  In Seward, Alaska

• Rissa tridactyla standing.jpg
• Black-legged Kittiwake.jpg

  Colony at Svalbard

• Arcticskua.jpg

  Chased by an Arctic skua at Svalbard

• Dreizehenmoewen.jpg

  At the Norwegian bird-island Runde

• Dreizehenmoewenpaar.jpg

  At Runde

• Black-legged Kittiwake and Chick.jpg

  On nest with chick

• Dreizehenmöwe.jpg

  Adult and chicks

• Rissa tridactyla-pjt.jpg

  Youth (Iceland)

• Black-legged Kittiwake from the Crossley ID Guide Britain and Ireland.jpg

  ID composite

References

• Harrison, Peter (1988). Seabirds: An Identification Guide. London: Christopher Helm. ISBN 0-7470-1410-8

External links

• Avibase
• Black-legged Kittiwake - Rissa tridactyla USGS Patuxent Bird Identification InfoCenter
• Black-legged Kittiwake Species Account - Cornell Lab of Ornithology
• Media related to at Wikimedia Commons
• Data related to Rissa tridactyla at Wikispecies
• Rissa tridactyla in the Flickr: Field Guide Birds of the World