Population status

Marsh Wren
(Cistothorus palustris)

The national population of Marsh Wren is best monitored in Canada by the Breeding Bird Survey (BBS), which covers about half the breeding population. BBS results suggest that the population has shown a fairly consistent increase since the early 1970s, with an over 100% increase in numbers. At the regional level, BBS results suggest large increases in all Bird Conservation Regions for which there are reasonably reliable results, including the Prairie Potholes Bird Conservation Region, which hosts the highest breeding density for this species in Canada. However, results from the Ontario and Quebec Marsh Monitoring Program (MMP) suggest little change in those populations since 1995 and 2004, respectively. It is difficult to compare results between the BBS and MMP because the latter are of shorter duration, cover a smaller portion of the species' range, and there are differences in wetland coverage between the MMP, which targets wetlands, and the roadside BBS. Based on BBS results, the Marsh Wren population is considered to have shown a large increase in Canada and is at an acceptable level relative to its national population goal (see Canada graph below). The continental population has also increased by over 100% since the early 1970s.

 

Population goal and acceptable levels of variation

Species/groupGoalLower levelUpper level
Marsh WrenMean abundance (2008-2012)10th percentile of observed abundance (1970-2012)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 analysis1970-20161.70.23
Canada Select to view graph of the geographic area: Canada 2006-2016; Breeding Bird Survey (BBS) - Canadian analysis2006-20163.917.4
Boreal Taiga Plains Select to view graph of the geographic area: Boreal Taiga Plains 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-20161.3-1.43.8
Northern Rockies Select to view graph of the geographic area: Northern Rockies 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-20161.2-13.3
Prairie Potholes Select to view graph of the geographic area: Prairie Potholes 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-20163.11.54.7
Lower Great Lakes / St. Lawrence Plain Select to view graph of the geographic area: Lower Great Lakes / St. Lawrence Plain 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-20161.9-0.23.9
 

Quebec Marsh Monitoring Program

Additional information on: Quebec Marsh Monitoring Program

Table 2: Population trends by geographic area
Geographic areaTime PeriodAnnual Trend Table 2 - footnote 1 Limits
LowerUpper
Quebec Select to view graph of the geographic area: Quebec 2004-2016; Quebec Marsh Monitoring Program2004-2016-0.035-0.064-0.002
 

Great Lakes Marsh Monitoring Program

Additional information on: Great Lakes Marsh Monitoring Program

Table 3: Population trends by geographic area
Geographic areaTime PeriodAnnual Trend Table 3 - footnote 1 Limits
LowerUpper
Great Lakes Basin in Ontario Select to view graph of the geographic area: Great Lakes Basin in Ontario 1995-2016; Great Lakes Marsh Monitoring Program1995-2016-0.008-0.0170
 

References