Black-legged kittiwake | |
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Adult black-legged kittiwake in Vardø, Norway | |
Calls, recorded on Skomer | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Charadriiformes |
Family: | Laridae |
Genus: | Rissa |
Species: | R. tridactyla |
Binomial name | |
Rissa tridactyla | |
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Range of R. tridactyla Summer range Wintering range | |
Synonyms | |
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The black-legged kittiwake (Rissa tridactyla) is a seabird species in the gull family Laridae. This species was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae as Larus tridactylus. The English name is derived from its call, a shrill 'kittee-wa-aaake, kitte-wa-aaake'. 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 black-legged kittiwake was formally described in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae . He placed with the gulls in the genus Larus and coined the binomial name Larus tridactylus. [2] Linnaeus specified the type location as northern Europe but this has been restricted to Great Britain. [3] The black-legged kittiwake is now placed together with the red-legged kittiwake in the genus Rissa that was introduced in 1826 by the English naturalist James Stephens. [4] The genus name is from the Icelandic word "rita" for a black-legged kittiwake. The specific tridactyla is from Ancient Greek tridaktulos meaning "three-toed". [5] The English name "kittiwake" is derived from its call, a shrill 'kittee-wa-aaake, kitte-wa-aaake'. [6]
Two subspecies are recognised. These are listed below together with their breeding ranges. [4]
The black-legged kittiwake is a coastal bird of the arctic to subarctic regions of the world. [7] It can be found all across the northern coasts of the Atlantic, from Canada to Greenland as well as on the Pacific side from Alaska to the coast of Siberia. [8] Black-legged kittiwakes' wintering range extends further south from the St-Lawrence to the southern coast of New Jersey as well as in China, the Sargasso sea and off the coast of west Africa. [8] [9] There are two subspecies of black-legged kittiwake. Rissa tridactyla tridactyla can be found on the Atlantic coast whereas Rissa tridactyla pollicaris is found on the Pacific coast.
Out of all the laridae, the kittiwakes are the most pelagic ones. Kittiwakes are almost exclusively found at sea with the exception of the breeding period, from May to September, where they can be found nesting on the sheerest sea cliffs. They are rarely found inland, though they have been reported on few instances as far as 20 km inland. [8] For the rest of the year, kittiwake spend most of their time on the wing out of sight from the coast.
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). [10] 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. [11] Studies show that integument coloration is associated with male's reproductive success. [11] Such hypothesis would explain the behavior of couples greeting each other by opening their mouth and flashing their bright mouth it to their partner while vocalizing. [12] As their Latin name suggests, they only possess three toes since their hind toe is either extremely reduced or completely absent. [9] The two subspecies being almost identical, R. tridactyla pollicaris is in general slightly larger than its counterpart R. tridactyle tridactyla. In winter, this species acquires a dark grey smudge behind the eye and a grey hind-neck collar. The bill also turns a dusky-olive color. [9]
Since kittiwakes winter at sea and rarely touch ground during this period, very little is known about their exact molting pattern.
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. [7] They can also be identified due to their solid black bill. [7] This plumage is a hatch-year plumage and will only remain for their first year. [13] Kittiwakes obtain their mature plumage at 4 years old, but will gradually change their juvenile plumage over time until maturity is reached. A second-year juvenile resembles a hatch-year regarding the plumage, though the bill is no longer solid black but instead has a greenish color. [13] The black marking on the coverts and the tail is still visible. The black marking will only molt during their third year, where the black is no longer present on the coverts, but the grey smudge on the head remains. [13] A third-year bird will also exhibit a small zone of bright yellow/orange at the base of its mostly greenish bill. It is only at four years old that the bill will reach an overall colour of bright yellow and complete its mature plumage. [13]
The old fisherman's name of "tarrock" for juvenile kittiwakes is still occasionally used.
Standard measurements [14] [15] | |
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length | 410–460 mm (16–18 in) |
weight | 400 g (14 oz) |
wingspan | 910 mm (36 in) |
wing | 295–322 mm (11.6–12.7 in) |
tail | 124–136 mm (4.9–5.4 in) |
culmen | 33–39 mm (1.3–1.5 in) |
tarsus | 32–36 mm (1.3–1.4 in) |
The kittiwake is named after its call that resembles a long "kit-ti-wake". [9] Apart from their typical call, kittiwakes have a wide array of vocalization. Their greeting call is used by the two members of a pair when meeting at the nest after an absence of one or both members. Before and during copulation, the female will often vocalize by making a series of short high pitched "squeak". [16] This call is also used by the female to beg for food from the male (courtship feeding). When predators are around, the kittiwake alarm call, an "oh oh oh oh" will be heard all across the colony. [16] Kittiwake will vocalize all day for various reasons and will only stop when the sun is down.
The red-legged kittiwake is the only other species in the genus Rissa and can be differentiated from its counterpart by its red legs, as the name suggests. [17] The head of the red-legged kittiwake is slightly smaller and bears a shorter bill. [17] The chicks of the Pacific black-legged kittiwake and red-legged kittiwake cannot be distinguished during their youngest downy phase. [17]
The juvenile black-legged kittiwake can be confused with the Bonaparte's gull juveniles although the kittiwakes' plumage has more black on the primaries and a different pattern going across the coverts. [12]
Kittiwake are known for their graceful flight. Unlike larger gulls, their flight is light with the wings beating in fast strokes. [12] When looking at them flying around the colony, kittiwakes often look as if they are playing in the wind with their agile flips and loops. Kittiwakes are highly gregarious and therefore are rarely seen flying alone far away from the colony. [12]
It is a coastal breeding bird around the north Pacific and north Atlantic oceans, found most commonly in North America and Europe. Kittiwakes are colonial nesters that form monogamous pairs and exhibit biparental care, meaning that both take part in nest building, incubation and chick rearing. They tend to nest in large numbers on cliffs by the sea side. 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.
Black-legged kittiwake gulls traditionally prefer nesting on natural cliffs and ledges, and there are historically few instances of kittiwakes nesting on man-made structures. In recent years, a shift in nesting behavior has been noted, particularly in the coastal areas of Northern Norway. [18]
Kittiwake pairs both participate in building the nest in which the female will lay their eggs. The breeding season begins in mid-June and usually end in August. [19]
Building the nest in order to welcome their fragile eggs is a tedious task and requires time and energy. The parents begin with a layer of mud and grass in order to form a platform that will cushion and help to isolate the eggs from the cold ground. [16] A cup is then built around the platform in order to keep the eggs from rolling out of the nest. [16] Finally, the nest is lined with soft and dry material such as moss, grass or seaweed. [16] The nest is solidified by a continuous trampling of the materials by the pair. [19] Throughout this period, the male will do courtship feeding by feeding the female at their nest site. [20] The reasons for such behavior are not quite understood but many hypotheses have been brought up to explain the phenomenon. Hypothesis such as the "nutrition hypothesis" and the "copulation enhancement hypothesis" have shown evidence that this behavior evolved either through natural or sexual selection. [20] [21]
Kittiwakes are single-brooded, meaning that the pair will only reproduce once per year. Egg formation within the female usually takes around 15 days and normal egg clutch size ranges from one to two sub-elliptical eggs, though three eggs clutches are not impossible. [19] The female will lay eggs on alternate days. [19] The eggs' color varies quite a bit, ranging from white, brownish to turquoise with dark brown speckles. [16] Once the eggs are laid, the parents will take turns and incubate their clutch for an average period of 27 days. [22] In case of egg loss, the female might relay another egg within 15 days after the loss. [16]
Chicks usually hatched through the larger end of the egg using their egg tooth. [16] [23] The egg tooth usually disappear after seven days post-hatching. [23] The alpha and beta chicks tend to hatch 1.3 days apart. [16] Kittiwake are born semi-precocial. 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. Regardless of predation, the chicks are most vulnerable within their first week due to their incapacity to properly thermoregulate during that period. [16] [23] Kittiwake chicks also exhibit siblicide, meaning that the first-born chick may kill its sibling in order to avoid competition for food from their parents. [23] If siblicide is to occur, it will most likely occur within the first 10 days of life of the smaller chick, in most cases the last born.
The downy plumage of chicks start to be replaced by the juvenile plumage only five days after hatching and will continue to do so for about 30 days, until the juvenile plumage is complete. It is not long after the completion of their juvenile plumage that the chicks will have their first flight at 34–58 days old. [24] Chicks will come back to the nest for several weeks after hatching and will eventually follow the adults at sea where they spend the winter. [24] Kittiwakes reach sexual maturity at around 4–5 years old. [23]
Kittiwakes are primarily pelagic piscivorous birds. Their main food source consists of fish, though it is not unlikely to find invertebrates such as copepods, polychete and squids in their diet, especially when fish is harder to find. [24] Due to their wide range, kittiwake diet is quite variable. In the Gulf of Alaska, their diet is usually composed of Pacific capelin, Pacific herring, Pacific sand land and much more. Kittiwakes of the coast of the United Kingdom, in Europe, rely mostly on sandeels. [25] In 2004, the kittiwake population in the Shetland islands, along with the murre (guillemot) and tern [16] population, completely failed to reproduce successfully due to a collapse in sandeel stock. [26] Like most gulls, kittiwake forage at the surface of the water where they tend to catch their prey while in flight or sitting on the water. Throughout winter, kittiwakes spend all of their time at sea where they forage. Unlike some gull species, they do not scavenge at landfills. [16] [24]
The foraging style of the kittiwakes is often compared to the terns' foraging strategy due to their frequent hovering and their head diving quickly at the surface of the water. [9] Instances of kittiwakes following whales are also common since they benefit from the fish fragments expelled by these huge marine mammals. [9] Fishers and commercial fishing boats are also the frequent witnesses of big groups of kittiwakes, often mixed with other gull species and terns, hovering around their ship in order to benefit from the scraps rejected in their sewage water or thrown overboard. [8]
There are few studies focussing on their water needs, though they seem to prefer salt water to fresh water. [9] [12] Captive kittiwakes are known to refuse fresh water but will willingly drink salt water. [12]
Kittiwakes are a frequent encounter of fisheries in northern regions. Their diet consisting almost exclusively of fish, fishermen tend to seek large aggregation of seabirds since they are often a sign of fish abundance. [12] On the other hand, kittiwake and other seabirds hang around fishing boats or platforms to collect scraps or any fish that might have been left out. [8] Due to the kittiwake pelagic lifestyle, they rarely interact with humans on the land, other than occasional sight near the ocean's coast.
In New England, the black-legged kittiwake is often called the "winter gull" since its arrival often signals to people that winter is coming. [12]
The city of Tromsø, along with other cities in the far north of Norway, has experienced a remarkable increase in the number of kittiwakes choosing to utilize city structures as nesting sites. This rise in urban nesting populations has seen the number of pairs skyrocket from a mere 13 to over 380 between 2017 and 2022. Researchers[ who? ] attribute[ where? ] this climate change related breeding failures, along with the absence of natural predators in the city, providing a safer environment for the gulls to breed and raise their young.[ citation needed ] The increasing nesting population has created challenges, as the gulls produce vast amounts of ammonia-smelling feces, discoloring buildings and streets, as well as the noise pollution generated by their constant vocalizations.[ according to whom? ]
To address these challenges, innovative measures have been implemented in Tromsø. One such initiative involves the establishment of "Kittiwake hotels," which are artificial bird cliff-structures built to encourage nesting away from urban facades. [18] The hotels have, along with mitigation measures preventing nesting on the city's structures, had success in attracting kittiwakes without having a negative impact on breeding.
Since the 1970s, it has been believed that the global population of black-legged kittiwake has declined of about 40% in only three generations (one generation is in average 12.9 years), putting the species in a dangerous place for the future. [1] The global population is estimated at 14,600,000-15,700,000 individuals and is in constant decline. The individual distribution of kittiwakes across the world varies quite a bit, with Europe representing more than 50% of the world's kittiwake and North America representing only 20%. In their recent species assessment, the IUCN Red List pointed out that all but one populations of kittiwakes were in decline, with the exception of the small Canadian arctic population that seems to be increasing at a rate of 1% per year. [1] The last IUCN Red List report in 2017, the species was moved from "least concern" to a "vulnerable" status on a global scale. [1]
Since the kittiwakes are fish specialist and tend to rely on prey species, their reproductive success highly depends on fish availability. Commercial fisheries have been known to have many direct and indirect impacts on their surrounding ecosystem. Direct impacts on the fish species themselves are well known, but the presence of fisheries also has an array of impacts on marine predators that not only rely on the species harvested but also on the "bycatch" species. [27] Fisheries harvesting species such as the sandeel, one of the main food source for kittiwakes in Europe, are known to have a huge impact of the reproductive success of local populations kittiwakes and other seabirds. [27] Long-term research on the effect of food availability on kittiwakes in the Gulf of Alaska showed a direct correlation between food availability and reproductive success, using a supplemental-feeding experiment. [28] Seabirds can also be a direct victim of fisheries. Their tendency to hang around them in hope of a good meal can lead to entanglements in fishing gear, often resulting in death by drowning. [29]
With global warming, the rising of ocean temperature is becoming a serious concern, affecting not only the marine flora and fauna but also the species exploiting the marine environment. Kittiwake are extremely sensitive to variation in food stocks. [30] Such variations can be due to over exploitation, as mentioned above, but can also be due to variations in sea surface temperature. With the rising the sea surface temperature, many fishes, such as sandeels, are negatively affected by a rise in ocean temperature. [31] Studies show that sandeels and many copepods populations are being negatively impacted due to increasing sea surface temperature. [30] Such effect on marine species can have tremendous impact on breeding kittiwakes which rely almost exclusively on pelagic fishes, making food more scarce in a time of high energetic needs. [31]
There are still no global conservation plans for the black-legged kittiwake though the species is closely monitored for population trends shifts. There are currently no international legislations regarding this species. However, the black-legged kittiwake is protected under the Migratory Bird Treaty Act of 1918 that has been ratified by the US, Canada, Mexico, Russia and Japan. [32] As for many gull species, the kittiwake is not a species of special interest for the public, therefore there are no education plans put in place in order to inform and educate people regarding this species.
The kittiwakes are two closely related seabird species in the gull family Laridae, the black-legged kittiwake and the red-legged kittiwake. The epithets "black-legged" and "red-legged" are used to distinguish the two species in North America, but in Europe, where Rissa brevirostris is not found, the black-legged kittiwake is often known simply as kittiwake. The 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 the black-legged kittiwake.
Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and distantly related to auks, and even more distantly to waders. Until the 21st century, most gulls were placed in the genus Larus, but that arrangement is now considered polyphyletic, leading to the resurrection of several genera. An older name for gulls is mews, which is cognate with German Möwe, Danish måge, Swedish mås, Dutch meeuw, Norwegian måke/måse, and French mouette, and can still be found in certain regional dialects.
Terns are seabirds in the family Laridae that have a worldwide distribution and are normally found near the sea, rivers, or wetlands. Terns are treated as a subgroup of the family Laridae which includes gulls and skimmers and consists of eleven genera. They are slender, lightly built birds with long, forked tails, narrow wings, long bills, and relatively short legs. Most species are pale grey above and white below, with a contrasting black cap to the head, but the marsh terns, the Inca tern, and some noddies have dark plumage for at least part of the year. The sexes are identical in appearance, but young birds are readily distinguishable from adults. Terns have a non-breeding plumage, which usually involves a white forehead and much-reduced black cap.
The Arctic tern is a tern in the family Laridae. This bird has a circumpolar breeding distribution covering the Arctic and sub-Arctic regions of Europe, Asia, and North America. The species is strongly migratory, seeing two summers each year as it migrates along a convoluted route from its northern breeding grounds to the Antarctic coast for the southern summer and back again about six months later. Recent studies have shown average annual round-trip lengths of about 70,900 km (44,100 mi) for birds nesting in Iceland and Greenland and about 48,700 km (30,300 mi) for birds nesting in the Netherlands. These are by far the longest migrations known in the animal kingdom. The Arctic tern nests once every one to three years.
The common tern is a seabird in the family Laridae. This bird has a circumpolar distribution, its four subspecies breeding in temperate and subarctic regions of Europe, Asia and North America. It is strongly migratory, wintering in coastal tropical and subtropical regions. Breeding adults have light grey upperparts, white to very light grey underparts, a black cap, orange-red legs, and a narrow pointed bill. Depending on the subspecies, the bill may be mostly red with a black tip or all black. There are several similar species, including the partly sympatric Arctic tern, which can be separated on plumage details, leg and bill colour, or vocalisations.
The black guillemot or tystie is a medium-sized seabird of the Alcidae family, native throughout northern Atlantic coasts and eastern North American coasts. It is resident in much of its range, but large populations from the high arctic migrate southwards in winter. The bird can be seen in and around its breeding habitat of rocky shores, cliffs and islands in single or smalls groups of pairs. They feed mainly by diving towards the sea floor feeding on fish, crustaceans or other benthic invertebrates. They are listed on the IUCN red list as a species of least concern.
The common murre, also called the common guillemot or foolish guillemot, is a large auk. It has a circumpolar distribution, occurring in low-Arctic and boreal waters in the North Atlantic and North Pacific. It spends most of its time at sea, only coming to land to breed on rocky cliff shores or islands.
The roseate tern is a species of tern in the family Laridae. The genus name Sterna is derived from Old English "stearn", "tern", and the specific dougallii refers to Scottish physician and collector Dr Peter McDougall (1777–1814). "Roseate" refers to the bird's pink breast in breeding plumage.
The ivory gull is a small gull, the only species in the genus Pagophila. It breeds in the high Arctic and has a circumpolar distribution through Greenland, northernmost North America, and Eurasia.
The royal tern is a tern in the family Laridae. The species is endemic to the Americas, though vagrants have been identified in Europe.
Forster's tern is a tern in the family Laridae. The genus name Sterna is derived from Old English "stearn", "tern", and forsteri commemorates the naturalist Johann Reinhold Forster.
The red-legged kittiwake is a seabird species in the gull family Laridae. It breeds in the Pribilof Islands, Bogoslof Island, and Buldir Island in the Bering Sea off the coast of Alaska, and the Commander Islands, Russia, and spends the winter at sea.
The greater crested tern, also called crested tern or swift tern, is a tern in the family Laridae that nests in dense colonies on coastlines and islands in the tropical and subtropical Old World. Its five subspecies breed in the area from South Africa around the Indian Ocean to the central Pacific and Australia, all populations dispersing widely from the breeding range after nesting. This large tern is closely related to the royal and lesser crested terns, but can be distinguished by its size and bill colour.
The Inca tern is a near-threatened species of tern in the subfamily Sterninae of the family Laridae. It is found along the Pacific coasts of Chile, Ecuador and Perú, and has appeared as a vagrant in Central America and Hawaii.
The swallow-tailed gull is an equatorial seabird in the gull family, Laridae. It is the only species in the genus Creagrus, which derives from the Latin Creagra and the Greek kreourgos which means butcher, also from kreas, meat; according to Jobling it would mean "hook for meat" referring to the hooked bill of this species. It was first described by French naturalist and surgeon Adolphe-Simon Neboux in 1846. Its scientific name is originally derived from the Greek word for gull, "Glaros" and via Latin Larus, "gull" and furca "two-tined fork". It spends most of its life flying and hunting over the open ocean. The main breeding location is in the Galápagos Islands, particularly the rocky shores and cliffs of Hood, Tower and Wolf Islands, with lower numbers on most of the other islands. It is more common on the eastern islands where the water is warmer.
The brown noddy or common noddy is a seabird in the family Laridae. The largest of the noddies, it can be told from the closely related black noddy by its larger size and plumage, which is dark brown rather than black. The brown noddy is a tropical seabird with a worldwide distribution, ranging from Hawaii to the Tuamotu Archipelago and Australia in the Pacific Ocean, from the Red Sea to the Seychelles and Australia in the Indian Ocean and in the Caribbean to Tristan da Cunha in the Atlantic Ocean. The brown noddy is colonial, usually nesting on elevated situations on cliffs or in short trees or shrubs. It only occasionally nests on the ground. A single egg is laid by the female of a pair each breeding season. In India, the brown noddy is protected in the PM Sayeed Marine Birds Conservation Reserve.
Fowlsheugh is a coastal nature reserve in Kincardineshire, northeast Scotland, known for its 70-metre-high (230 ft) cliff formations and habitat supporting prolific seabird nesting colonies. Designated as a Site of Special Scientific Interest (SSSI) by Scottish Natural Heritage, the property is owned by the Royal Society for the Protection of Birds. Fowlsheugh can be accessed by a public clifftop trail, or by boats which usually emanate from the nearby harbour at the town of Stonehaven. Tens of thousands of pelagic birds return to the site every spring to breed, after wintering at sea or in more southern climates, principal species being puffins, razorbills, kittiwakes, fulmars and guillemots.
The Antarctic tern is a seabird in the family Laridae. It ranges throughout the southern oceans and is found on small islands around Antarctica as well as on the shores of the mainland. Its diet consists primarily of small fish and crustaceans. It is very similar in appearance to the closely related Arctic tern, but it is stockier, and it is in its breeding plumage in the southern summer, when the Arctic tern has shed old feathers to get its non-breeding plumage. The Antarctic tern does not migrate like the Arctic tern does, but it can still be found on a very large range. This tern species is actually more closely related to the South American tern.
The term seabird is used for many families of birds in several orders that spend the majority of their lives at sea. Seabirds make up some, if not all, of the families in the following orders: Procellariiformes, Sphenisciformes, Pelecaniformes, and Charadriiformes. Many seabirds remain at sea for several consecutive years at a time, without ever seeing land. Breeding is the central purpose for seabirds to visit land. The breeding period is usually extremely protracted in many seabirds and may last over a year in some of the larger albatrosses; this is in stark contrast with passerine birds. Seabirds nest in single or mixed-species colonies of varying densities, mainly on offshore islands devoid of terrestrial predators. However, seabirds exhibit many unusual breeding behaviors during all stages of the reproductive cycle that are not extensively reported outside of the primary scientific literature.