| Kittiwake | |
|---|---|
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| Rissa tridactyla inVardø, Norway | |
| The call of a kittiwake, recorded on Skomer Island, Pembrokeshire, Wales | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Charadriiformes |
| Family: | Laridae |
| Subfamily: | Larinae |
| Genus: | Rissa Stephens, 1826 |
| Type species | |
| Rissa brunnichii[1] =Larus tridactylus Stephens, 1826 | |
| Species | |
Thekittiwakes (genusRissa) are two closely relatedseabird species in thegull family Laridae, theblack-legged kittiwake (Rissa tridactyla) and thered-legged kittiwake (Rissa brevirostris). Theepithets "black-legged" and "red-legged" are used to distinguish the two species in North America, but in Europe, whereRissa brevirostris is not found, the black-legged kittiwake is often known simply askittiwake. The name is derived from its call, a shrill 'kittee-wa-aaake, kitte-wa-aaake'.[2] The genus nameRissa is from the Icelandic nameRita for the black-legged kittiwake.[3]
The two species are physically very similar. They have a white head and body, grey back, grey wings tipped solid black and a bright yellow bill. Black-legged kittiwake adults are somewhat larger (roughly 40 cm or 16 in in length with a wingspan of 90–100 cm or 35–39 in) than red-legged kittiwakes (35–40 cm or 14–16 in in length with a wingspan around 84–90 cm or 33–35 in). Other differences include a shorter bill, larger eyes, a larger, rounder head and darker grey wings in the red-legged kittiwake. While most black-legged kittiwakes do, indeed, have dark-grey legs, some have pinkish-grey to reddish legs, making colouration a somewhat unreliable identifying marker.
In contrast to the dappled chicks of other gull species, kittiwake chicks are downy and white since they are under relatively little threat of predation, as the nests are on extremely steep cliffs. Unlike other gull chicks which wander around as soon as they can walk, kittiwake chicks instinctively sit still in the nest to avoid falling off.[4] Juveniles take three years to reach maturity. When in winter plumage, both birds have a dark grey smudge behind the eye and a grey hind-neck collar. The sexes are visually indistinguishable.
Kittiwakes are coastal breeding birds ranging in theNorth Pacific,North Atlantic, andArctic oceans. They form large, dense, noisycolonies during the summer reproductive period, often sharing habitat withmurres. They are the only gull species that are exclusively cliff-nesting. A colony of kittiwakes living inNewcastle upon Tyne andGateshead in the north east of England has made homes on both theTyne Bridge andBaltic Centre for Contemporary Art.[5] This colony is notable because it is the furthest inland colony of kittiwakes in the world.[6]
| Common name | Scientific name and subspecies | Range | Size and ecology | IUCN status and estimated population |
|---|---|---|---|---|
| black-legged kittiwake
| Rissa tridactyla Linnaeus, 1758 | Breeding colonies can be found in the Pacific from theKuril Islands, around the coast of theSea of Okhotsk throughout theBering Sea and theAleutian Islands to southeastAlaska,[7] and in the Atlantic from theGulf of St. Lawrence throughGreenland and the coast ofIreland down toPortugal, as well as in the high Arctic islands.[8] In the winter, the range extends further south and out to sea. | Size: It is one of the most numerous of seabirds. Habitat: At sea or nesting on the sheerest sea cliffs. Diet: Fish, copepods, polychete and squids | VU |
| red-legged kittiwake
| Rissa brevirostris Bruch, 1853 | Very limited range in theBering Sea, breeding only on thePribilof,Bogoslof, andBuldir islands in the United States, and theCommander Islands inRussia. | Size: Adults are 35–39 cm (14–15 in) long, with an 84–92 cm (33–36 in) wingspan and a weight of 325–510 g (11.5–18.0 oz).[9] Habitat: On these islands, it shares some of the same cliff habitat as the black-legged kittiwake, though some localized segregation is seen between the species on given cliffs. Diet: | VU |
Genera ofshorebirds and their extinct allies | |||||||||||||||||||||||||||||||||||||||||||||
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