The MacGillivray's Warbler is best monitored in Canada by the Breeding Bird Survey, the results of which indicate a long-term and continuing decrease in abundance, with an overall loss of nearly 30% of the population since the early 1970s. At the regional level, the decline appears steepest in the coastal Northern Pacific Rainforest Bird Conservation Region, followed by the Great Basin; the population in the Northern Rockies has remained relatively stable since 1970. The MacGillivray's Warbler population has been below the lowest acceptable level relative to its national population goal since the mid-2000s (see Canada graph below).
Additional information on: Breeding Bird Survey (BBS) - Canadian analysis
