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Much of the Willow Ptarmigan's range lies north of regularly surveyed areas (Hannon et al. 1998). The Christmas Bird Count (CBC) provides population trends for this species but the estimates are imprecise and the surveys only occur towards the southern edge of the range. The CBC results suggest that the Willow Ptarmigan population in Canada has undergone a moderate decrease since about 1970, but this result is considered to be of low reliability due to low precision and low coverage of the species' range. The species is known to show population fluctuations, possibly in response to climatic fluctuations and/or changes in predator numbers that are themselves linked to changes in other prey species. However, these are not evident in the annual index graph (displayed below). Although the exact population status relative to about 1970 is unclear, the species remains abundant across most of its range.
Additional information on: Christmas Bird Count (CBC)