Much of the Willow Ptarmigan's range lies north of regularly surveyed areas (Hannon et al. 1998). The Christmas Bird Count (CBC) provides population trend information for this species, but the estimates are imprecise and the counts only occur at the southern edge of the range. Willow Ptarmigan have only been recorded on only 21 CBC circles in Canada. CBC results suggest that the Willow Ptarmigan population in Canada has undergone a moderate decrease since the early 1970s, though this result is considered to be of low reliability for the above reasons. The few data from the Breeding Bird Survey (BBS) suggest little change in the population in Canada and continent-wide. 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. Based on CBC results, the Willow Ptarmigan is thought to be below the lowest acceptable level relative to its national population goal (see CBC Canada graph below). However, the exact population status relative to the early 1970s remains unclear, and the species remains abundant across most of its range.
Additional information on: Christmas Bird Count (CBC)
Additional information on: Breeding Bird Survey (BBS) - Canadian analysis
