Snow bunting (Plectrophenax nivalis)

The snow bunting is the most northerly passerine bird in the world, and is the only passerine with a wide breeding distribution in Svalbard. It breeds in a circumpolar range, south to Scotland and Iceland, and it is a common breeder in suitable habitats in northern Scandinavia, Greenland, Svalbard, arctic parts of Russia and the northerly parts of North America. The snow bunting is a stocky sparrow-like passerine.

Snow buntingSnow bunting. Photo: Bjørn Frantzen / Norwegian Polar Institute

The snow bunting is a stocky sparrow-like passerine (birds with four toes that are able to perch on branches etc.). Adults are 16-17 cm long and weigh 25-40 g. The male's breeding plumage is predominantly white, with some black on the back, wing-tips and central tail-feathers. In flight the clear contrast between the white and black of the wings is evident. The female resembles the male, but has a grey-brown head and back. Both sexes have a black bill and legs. In winter plumage the male has brownish upper-parts that have black streaks. The crown, sides of the head and the breast have a yellow-brown tinge. The female in winter plumage is more buff than in summer. The bill of both sexes is yellow during winter. Juvenile birds have a grey head and breast and they have brown-black upper-parts. Their regular calling is a soft "teen", while the male breeding song is a lark-like warble. The melodious song of the snow bunting, Svalbard’s only songbird, gives a special character to the arctic landscape in spring.

Distribution

The snow bunting is the most northerly passerine bird in the world. It breeds in a circumpolar range, south to Scotland and Iceland, and it is a common breeder in suitable habitats in northern Scandinavia, Greenland, Svalbard, arctic parts of Russia and the northerly parts of North America. Four sub-species are recognized. The Svalbard population belongs to the nominate race P. n. nivalis. It is the only passerine with a wide breeding distribution in Svalbard. Snow buntings breed over most of the archipelago, except for some far eastern areas. It is a migratory bird that winters in temperate areas. Recoveries of ring-marked birds suggest that Svalbard's snow buntings migrate in a south-easterly direction over northwest Russia, towards the Russian steppes north of the Caspian Sea and in Kazakhstan. Snow buntings from Svalbard have been recovered during spring in areas around the White Sea and on the Kanin Peninsula. It is not known whether the Svalbard population migrates directly from the White Sea to Svalbard, or whether they migrate via northern Norway. Most snow buntings leave Svalbard in August-September. The males arrive from the wintering grounds early in spring, some of them as early as the end of March, but the majority arrive during April. Females move north into the breeding areas some weeks later than the male. 

Ecology

Snow buntings occur in pairs during the breeding season on stony tundra terrain, on mountain slopes, by seabird-cliffs and around human settlements. This species inhabits both coastal and inland areas and is even found on nunataks (rocky mountain tops poking out of glaciers). It breeds close to seabird colonies with luxuriant vegetation and in nunataks that are devoid of any vegetation. Outside the breeding season snow buntings can be seen in flocks on open plains and beach meadows. It is a very hardy little bird that arrives in spring when the ground is still covered with snow and the ambient temperature is often well below freezing in Svalbard. Snow buntings protect themselves against extreme weather by digging small hollows in the snow, similar to grouse and ptarmigan. The arctic fox, gulls and skuas are important predators of eggs and chicks, and the Gyr falcon Falco rusticolus is an important predator of snow buntings when they are migrating. They are predominantly seed-eaters, but snow buntings also capture insects particularly when feeding their young.

Life history and reproduction

The males establish breeding territories soon after their spring arrival and sing from high perches to attract females. They usually place the nest in rocky crevices, under rock slabs, in screes or in buildings, well out of sight. Snow buntings will also use artificial nest boxes. The nest is well insulated with a variety of materials, usually mostly feathers and hair. The nest is built mainly by the female. The four to seven egg clutch (usually five or six eggs) contains eggs that are grey-white with reddish-brown speckles. Egg-laying usually takes place in late May or early June, but there may be several clutches during the course of a season. The female incubates for 12-14 days. The timing of breeding is such that the peak of hatching corresponds with the initial emergence of adult insects. The young, which are fed by both parents, leave the nest after 12 to 14 days, often before they are fully fledged. The young are fed insects.

Management status and monitoring

The snow bunting has a wide breeding distribution in Svalbard. The size of the Svalbard population is not known, but it has been estimated to be somewhere between 1,000 and 10,000 pairs. Like other passerines the snow bunting shows marked fluctuations in abundance, but no specific trend has been noted in the population.

MOSJ indicators (Environmental Monitoring of Svalbard and Jan Mayen):

Awaiting results from MOSJ…