The Nelson's Sparrow is best monitored by the Breeding Bird Survey (BBS) in Canada, although it does not cover the species' northern populations. BBS results suggest a relatively steady increase in numbers since about the early 1970s. However, results from the Christmas Bird Count, which monitors the species on its United States' wintering grounds, suggest little overall change in the population. Although CBC results may be somewhat influenced by trends in birds that breed in the U.S., more than 80% of Nelson's Sparrows breed in Canada. Regional results suggest the population in the Prairie Potholes Bird Conservation Region (BCR), the core of the species' range, has increased, while numbers in the Atlantic Northern Forest and Boreal Taiga Plains BCRs have shown little overall change relative to 1970 (all BCRs with reasonably reliable trends are displayed below). Limited information on the population breeding along the coast of Hudson's and James Bays comes from the Atlas of the Breeding Birds of Ontario (see below); though now somewhat out of date, atlas results suggest a moderate increase in the probability of observation between the first and second atlases. The Maritimes atlas documents a relatively stable distribution and only small local changes in the probability of observation (Blaney 2015) for the 20-year period between the two atlases. Considering BBS as the primary data source with some support from the atlases, the population as a whole is perhaps best assessed as having shown a moderate increase in abundance since 1970. Nelson's Sparrow is at an acceptable level relative to its national population goal (see Canada graph below).
Additional information on: Breeding Bird Survey (BBS) - Canadian analysis
Additional information on: Christmas Bird Count (CBC)
