User:FungiFish2020/Rock ptarmigan

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The rock ptarmigan (Lagopus muta) is a medium-sized game bird in the grouse family. It is known simply as the ptarmigan in the UK and in Canada, where it is the official bird for the territory of Nunavut, and the official game bird for the province of Newfoundland and Labrador. In Japan, it is known as the raichō (雷鳥), which means "thunder bird". It is the official bird of Gifu, Nagano, and Toyama Prefectures and is a protected species nationwide. Unlike many arctic inhabiting bird species, ptarmigan do not gain substantial mass to hibernate over winter.

Energy Storage and Assimilation
Rock ptarmigan have a limited capacity for fat storage, which requires overwintering birds to forage frequently. Most of the miniscule mass gained over winter is to the ovary, oviduct and hypertrophy, in preparation for the spring breeding season. Rock ptarmigan maximize assimilation of nutrient poor foods with their elongated ceca. Metabolic requirements can be partially supplemented by fermentation, the energy gain from fermentation alone, however, is not independently significant.

The Svalbard subspecies of rock ptarmigan is the only subspecies that exhibits a significant seasonal mass gain. Larger fat deposits can help them survive during periods of low food availability. However, this alone is not an adequate source of energy to survive during winter. Locomotion appears to have no energetic cost in these birds. This adaptation is key for a species that must move frequently to forage. Fat assimilation in these birds is correlated to changes in liver weight. Most rock ptarmigan have no more than 20 grams of adipose tissue year round. Without food, these reserves can supplement energy for 2 days. The Svalbard rock ptarmigan, however, gains about 100 grams of adipose tissue. This can serve as an energy source for up to 10 days of starvation.

The Svalbard subspecies inhabits the northern extent of the rock ptarmigans range. During winter, food availability is lower in Svalbard than in other parts of their range, which accounts for the necessary increased fat reserves not found in other sub populations.

Other additions
-Adding Lagopus muta hyperborea, the Svalbard Rock Ptarmigan to the list of sub species.

== References ==