Population status

MacGillivray's Warbler
(Geothlypis tolmiei)

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).

 

Population goal and acceptable levels of variation

Species/groupGoalLower levelUpper level
MacGillivray's WarblerMean abundance (first 5 years of survey)Goal minus 25% Not applicable

Breeding Bird Survey (BBS) - Canadian analysis

Additional information on: Breeding Bird Survey (BBS) - Canadian analysis

Table 1: Population trends by geographic area
Geographic areaTime Period Table 1 - footnote 1 Annual trend Table 1 - footnote 2 Limits
LowerUpper
Canada Select to view graph of the geographic area: Canada 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-2016-0.8-1.4-0.1
Canada Select to view graph of the geographic area: Canada 2006-2016; Breeding Bird Survey (BBS) - Canadian analysis2006-2016-0.5-21.3
Northern Pacific Rainforest Select to view graph of the geographic area: Northern Pacific Rainforest 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-2016-2-2.7-1.2
Great Basin Select to view graph of the geographic area: Great Basin 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-2016-1.4-2.3-0.6
Northern Rockies Select to view graph of the geographic area: Northern Rockies 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-20160-0.80.8
North America Select to view graph of the geographic area: North America 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-2016-0.7-1.2-0.3
 

References