Kittiwake (Rissa tridactyla) juvenile, Sabine's Gull (Xema sabini) & Fulmar (Fulmarus glacialis)
[order] Charadriiformes | [family] Laridae | [latin] Rissa tridactyla | [UK] Black-Legged Kittiwake | [FR] Mouette tridactyle | [DE] Dreizehenmöwe | [ES] Gaviota Tridáctila | [IT] Gabbiano tridattilo | [NL] Drieteenmeeuw
spanwidth min.: 93 cm
spanwidth max.: 105 cm
size min.: 37 cm
size max.: 42 cm
incubation min.: 25 days
incubation max.: 32 days
fledging min.: 33 days
fledging max.: 54 days
eggs min.: 1
eggs max.: 3
The Black-legged Kittiwake is a medium-sized gull, with the typical 'gull-like' appearance of white head and body, slate-gray back and wings, black wingtips, and a yellow bill. The legs are black. The juvenile has bold, black edgings on its wings and the nape of its neck, and a black bill. Black-legged Kittiwakes fly with stiffer wing-beats than other gulls.
Black-legged Kittiwakes are surface feeders, dropping from flight to take items off the surface of the water, or plunging into the water for prey just below the surface, but not diving deeply. They also forage while swimming.
A pelagic gull, this kittiwake spends most of the year at sea. The Black-legged Kittiwakes gather in areas of upwellings, sometimes over the edge of the continental shelf. They can be found from the coast to over a hundred miles offshore. They breed on narrow cliff ledges in the far north.
Rissa tridactyla is a widespread but patchily distributed breeder along the Atlantic coasts of western and northern Europe, which accounts for less than half of its global breeding range. Its European breeding population is very large (>2,100,000 pairs), and underwent a moderate increase between 1970-1990. Although the species declined in Greenland, Norway and the United Kingdom during 1990-2000, and underwent a moderate decline (>10%) overall, this decline is probably outweighed by the earlier increase.
Atlantic populations have experienced growth in recent years. Pacific populations of Black-legged Kittiwakes fluctuate dramatically. They are relatively insensitive to the direct effects of oil spills, but they are indirectly affected by a reduction in prey species. In years when food is scarce, their nesting success is significantly reduced. In addition to the obvious effects of lack of food, when prey is scarce, the adults range farther from the nest and are away for longer periods of time, leaving the eggs and the young exposed, and thus more vulnerable to predators. Years of near-total breeding failure for colonies have been observed in years when the diving birds in the same area do not experience a similar decline, indicating that surface feeders may be responding to different environmental disturbances than diving birds. For this reason, Black-legged Kittiwakes have been proposed as a good indicator species of marine health.
Small surface-schooling fish make up the majority of the Black-legged Kittiwake's diet. When these fish aren't available, the kittiwakes eat krill and other sea creatures. They occasionally feed on waste from ships. Black-legged Kittiwakes do not feed at garbage dumps as do many other gull species.
Black-legged Kittiwakes are monogamous during the breeding season, but do not maintain their pair bonds during the non-breeding season. Many will, however, re-pair with the same mate in the following year. They first breed at 3-5 years of age. On a narrow cliff edge, both parents help build a nest of mud, seaweed, and grass with a shallow depression in the middle. The female lays 1-3 eggs, and both sexes help incubate for about 4 weeks. The young stay in the nest for 5-8 weeks, and both parents provide food. After fledging, the young may return to the nest for a few more weeks. The nest ledges are so narrow that the birds must face towards the cliff, with tails pointed out, to fit.
Sabine's Gull (Xema sabini)
[order] Charadriiformes | [family] Laridae | [latin] Larus sabini | [UK] Sabines Gull | [FR] Mouette de Sabine | [DE] Schwalbenmöwe | [ES] Gaviota de Sabine | [IT] Gabbiano di Sabine | [NL] Vorkstaartmeeuw
spanwidth min.: 80 cm
spanwidth max.: 87 cm
size min.: 30 cm
size max.: 36 cm
incubation min.: 23 days
incubation max.: 25 days
fledging min.: 0 days
fledging max.: 0 days
eggs min.: 1
eggs max.: 3
The Sabine's Gull is a small gull with a graceful, tern-like flight. This gull has a slate-gray back, a white belly and tail, and black wingtips. The adult has a black bill with a yellow tip. The middle of the wings is white, giving the bird a distinctive 'M' pattern across its wings in flight. In breeding season, the adult has a dark gray hood, edged in black. The adult in non-breeding plumage has a partially gray and white head. The juvenile is brown across the back, neck, and head, with a white face.
The Sabine's Gull often hovers low over the water, dropping down to take food from the water's surface without landing. It also forages while swimming. In summer, this gull often feeds by walking along the tidal flats and picking up food. The Sabine's Gull has been known to spin in circles in shallow water, stirring up food from the bottom.
Sabine's Gulls nest in the high Arctic in marshy tundra ponds close to the coast. Outside the breeding season, they spend most of their time at sea, out of sight of land. When at sea, they concentrate over the continental shelf or over upwellings of cold, nutrient-rich water.
Their remote breeding range and seagoing nature may have protected the population, however the possibility of oil-drilling in the Arctic threatens the Sabine's Gull's nesting habitat. During migration and winter, they are vulnerable to water pollution and fluctuations of prey abundance. Since their winter diet is not well known, more research is needed to fully understand what is necessary for conservation
In summer, the Sabine's Gull feeds mostly on insects and aquatic insect larvae. During migration, small crustaceans, fish, and other sea creatures are also part of the diet. Their winter diet is not well known.
Nests are located on the open ground, in small colonies, typically close to the water. Sabine's Gull colonies are often located near or within Arctic Tern colonies. The nest is a shallow depression, sometimes unlined, or lined with seaweed, moss, or feathers. The female typically lays two eggs, which both parents help incubate for about 3½ weeks. Shortly after the young hatch, the parents lead them to water, where they mostly feed themselves.
Fulmar (Fulmarus glacialis)
[order] Procellariiformes | [family] Procellariidae | [latin] Fulmarus glacialis | [UK] Fulmar | [FR] Pétrel fulmar | [DE] Eissturmvogel | [ES] Fulmar | [IT] Fulmaro | [NL] Noordse Stormvogel
spanwidth min.: 101 cm
spanwidth max.: 117 cm
size min.: 43 cm
size max.: 52 cm
incubation min.: 49 days
incubation max.: 53 days
fledging min.: 46 days
fledging max.: 51 days
eggs min.: 1
eggs max.: 1
The Northern Fulmar is similar in appearance to a gull but stockier, with a thick neck, and more rounded wings and tail. The Northern Fulmar varies in color from mostly white, to gray and white like many gulls, to an overall gray-brown, with every possible shade in between.
Although the Northern Fulmar appears gull-like at first glance, its flight behavior is quite different. Stiff-winged glides and quick wing-beats are characteristic of its flight. When feeding on the surface of the water, the Northern Fulmar grabs prey at or just below the water's surface. It also dives into the water and propels itself using its feet and wings
Found in the cold waters of the open ocean, Northern Fulmars breed on steep sea cliffs on islands or mainland promontories. They use cliffs farther north than do most high-Arctic seabird species, often crossing ice-covered water to get to their breeding sites.
Fulmarus glacialis is a widespread breeder in coastal areas of north-west Europe, which accounts for less than half of its global breeding range. Its European breeding population is very large (>2,800,000 pairs), and underwent a large increase between 1970-1990. Although the species declined slightly in the United Kingdom during 1990-2000, other European populations-including key ones in Iceland, Svalbard and the Faroes-increased or were stable, and the species underwent a large increase overall.
Populations in the Atlantic Ocean have experienced dramatic increases in recent decades. In the Pacific, several new colonies have been established since 1970, although there is no indication of dramatic increases in the Pacific comparable to those in the Atlantic. The commercial fishing industry is a major factor in the population of Northern Fulmars, providing them with most of their food. Large aggregations of birds can be found behind fishing boats, feeding on offal. While Northern Fulmars are not currently threatened, as colony nesters with high density in a few small areas, they are at potential risk if that habitat is degraded.
The diet of the Northern Fulmar is varied, consisting of crustaceans, fish, small squid, and jellyfish. Fulmars commonly follow fishing boats and feed off the fish waste thrown from the boats.
This species has a large range, with an estimated global breeding Extent of Occurrence of 50,000-100,000 km². It has a large global population estimated to be 8,000,000-32,000,000 individuals (del Hoyo et al. 1992). Global population trends have not been quantified, but there is evidence of a population increase (del Hoyo et al. 1992), and so the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern. [conservation status from birdlife.org]
Colonial breeders that nest on open sea cliffs, Northern Fulmars breed mainly in high-Arctic Canada and on islands in the Bering Sea. These birds are slow to mature and do not start breeding until they are 8-10 years old. Unlike many of the other members of this family, they are active around their nesting colonies during the day. The nest is located on the ledge of a cliff or in a hollow on a bank or slope. When nesting on a rock ledge, the fulmars do not build a nest, but when they nest on a bank or slope, they make a shallow scrape, occasionally lined with small stones. The female lays one egg, and both parents incubate for about 7 weeks. Once the egg hatches, both parents feed the chick by regurgitation. The chick takes flight for the first time at the age of about seven weeks.
Dispersive. In temperate and subarctic latitudes, breeding adults present at sea within feeding range of colonies for most of year. Breeding ledges often visited during autumn and winter; inshore waters mostly deserted during moulting period August-October, though in recent years some present all year at older colonies. Juveniles disperse over great distances; probably immatures constitute majority seen mid-ocean.