Population status

Willow Flycatcher
(Empidonax traillii)

The Breeding Bird Survey (BBS) is the most reliable survey for determining the population status of the Willow Flycatcher in Canada. BBS results demonstrate a long-term decrease in the Canadian population that appears to be concentrated in the western portion of its range; increases are seen in the Lower Great Lakes/St. Lawrence Plain and Boreal Hardwood Transition Bird Conservation Regions (BCRs). All BCRs with relatively reliable results are shown below. Most Willow Flycatchers breed in the United States; continent-wide BBS results indicate a similar long-term decrease. The Willow Flycatcher is currently below the lowest acceptable level relative to its national population goal (see BBS Canada graph below).

 

Population goal and acceptable levels of variation

Species/groupGoalLower levelUpper level
Willow FlycatcherMean 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 analysis1970-2016-1.4-2-0.8
Northern Pacific Rainforest Select to view graph of the geographic area: Northern Pacific Rainforest 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-2016-2.4-3.3-1.4
Great Basin Select to view graph of the geographic area: Great Basin 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-2016-0.6-1.50.3
Northern Rockies Select to view graph of the geographic area: Northern Rockies 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-2016-0.6-1.70.5
Boreal Hardwood Transition Select to view graph of the geographic area: Boreal Hardwood Transition 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-20161.2-1.74.3
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 analysis1970-20160.7-0.21.6
North America Select to view graph of the geographic area: North America 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-2016-1.4-1.7-1.1
 

References