Svalbard rock ptarmigan
Svalbard rock ptarmigan in other languages
| Latin | Lagopus muta hyperborea |
| Norwegian | Svalbardrype |
| German | Alpenschneehuhn |
| French | Lagopède de Alpes |
The Svalbard rock ptarmigans are 35–40 cm long and weigh between 490 and 1200 g. There is significant seasonal variation in weight. Both sexes have white winter plumage except for black outer tail feathers.
The male (cock) has a black line from eye to the beak, and in the breeding season also a large, fleshy red comb above the eye. The female (hen) also has a red colour comb, but it is less visible.
The hen changes into summer plumage in April-May. The feathers are more red-brown than the Scandinavian rock ptarmigan and actually look more like the willow ptarmigan. The cock retains the white plumage until July and does not acquire complete brown summer plumage until mid-August. By the end of September both sexes are again in winter plumage. Juvenile birds are more grey-brown than their parents and they have a brown tail.
The cock´s call is a characteristic burping “aarr-aa-ka-ka”, while the hen makes a more quiet call that sound like “kee-ah, kee-ah”.
Distribution
The rock ptarmigan has a circumpolar distribution in northern temperate and arctic regions, in addition to the Alps and the Pyrenees. The sub-species L. m. hyperboreus is restricted to Svalbard and Franz Josef Land. The Svalbard rock ptarmigan is the only land-inhabiting bird which resides in the archipelago throughout the year. It is common over most of the archipelago except for the most north-easterly parts of Svalbard. Breeding has not been observed on Kvitøya, Kongs Karls Land, Hopen or Bjørnøya.
The Svalbard rock ptarmigan uses separate habitats during the winter compared to during the breeding season. In many places it leaves the nesting areas in September–October. The location of the wintering areas and possible seasonal movement patterns are unknown, but it is assumed that they seek relatively snow-free areas such as under bird-cliffs and other areas with rich vegetation in winter.
Ecology
The cocks return to the breeding grounds in the middle of March and to establishes a territory. The hens arrive in early April. The best habitats are located on south-facing slopes where the snow melts early. Altitude, terrain ruggedness and vegetation characteristics are the most important landscape attributes determining the quality of the habitat for nesting.
Territories in optimal areas (with many wind-blown ridges and abundant vegetation) are established first followed by sub-optimal and marginal territories. Cocks return to the same territory in subsequent years, whereas hens change territory (and partners) but always come back to the same general breeding grounds.
It is not known whether the Svalbard ptarmigan exhibits annual population cycles similar to those found in rock ptarmigans other places (6-10 years cycles in Scotland, Iceland and Alaska).
The diet of rock ptarmigan varies seasonally. Alpine bistort is the most important food source in summer and autumn. In late autumn and early winter various species of meadow-grasses and hair-grasses become important. From November to February purple and tufted saxifrage are the main food source, while polar willow increases in the diet from March–April and is eaten through to the spring.
The Svalbard rock ptarmigan has few natural predators. The most important predators are the Arctic fox, glaucous gulls and Arctic skuas.
Life history and reproduction
Mating takes place in late May. The nest is placed in the upper part of the territory on dry ground and consists of a 1–2 cm scrape in the ground that is lined with dead leaves.
Egg-laying occurs in early to mid June, but may be delayed in years with late snow melting. Repeated egg-laying can occur if eggs are lost early in the season. There are usually 9–11 eggs in a clutch (successive clutches contain fewer). A cock can have more than one hen within his territory, but the second hen lays her clutch later than the first and produces fewer chicks. The eggs have a yellow-brown background with many brown-black speckles and blotches.
The eggs are incubated by the hen for 21 days and the hatching weight of chicks is about 16 g. The hen and her brood leave the nest one to two days after hatching. Chicks are fledged after 10–12 days, but remain with the mother for 10–12 weeks.
The pair bond between the adult male and female dissolves when the hen leaves the nest with the chicks. At this time the cock leaves the breeding site in order to find better foraging grounds. Ptarmigans become sexually mature during their first year of life (about 10 months).
Management status and monitoring
Population estimates do not exist for the rock ptarmigan on the whole Svalbard Archipelago. But, a 5-year monitoring programme in a restricted area has measured three to five territorial cocks per km2.
The Svalbard rock ptarmigan is an important small game species, and harvesting takes place annually in autumn and early winter.