Population status

Prairie Warbler
(Setophaga discolor)

There are little current data to assess the status of the very small Prairie Warbler population in Canada. The only data come from the Atlas of the Breeding Birds of Ontario and from species-specific surveys undertaken in the early-1980s (Lambert and Smith 1984) and late-1980s (Harris 1998). Atlas methods are well-suited to rare species such as this one though the probability of observation of a species recorded in the Atlas does not directly equate to population change. Results suggest little change in the probability of observation between Atlas periods; some local losses occurred due to habitat succession while other areas became colonized with small numbers of Prairie Warbler (Sutherland and Harris 2007). These results generally agree with the species-specific surveys from the 1980s. However, the Ontario Atlas only covers the period between 1981-1985 and 2001-2005, and the results are considered insufficient to determine the current status. In the United States, the main population is well-monitored by the Breeding Bird Survey (BBS), so important short-term population changes should be readily detected and may serve as an early warning for Canada. BBS data from throughout North America indicate that the continental population has shown a consistent and ongoing decrease since the 1970s. Also of note, a breeding population of 150 or more pairs was lost from the Wasaga Beach area due to cottage development between the 1920s and the first Atlas (Lambert and Smith 1984), a loss that is not shown in the Atlas results. Because of the lack of information, a national population goal for the Prairie Warbler has not yet been determined.

 

Population goal and acceptable levels of variation

Species/groupGoalLower levelUpper level
Prairie WarblerTo be determinedTo be determinedNot 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
North America Select to view graph of the geographic area: North America 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-2016-1.6-1.8-1.3
North America Select to view graph of the geographic area: North America 2006-2016; Breeding Bird Survey (BBS) - Canadian analysis2006-2016-0.8-1.70
 

Atlas of the Breeding Birds of Ontario

Additional information on: Atlas of the Breeding Birds of Ontario

Table 2: Population trends by geographic area
Geographic areaTime PeriodAnnual trend (%) Table 2 - footnote 1 Limits
LowerUpper
Ontario1981/85 - 2001/05-0.2-21.7
 

References

  • Harris, C.G. 1998. Final Report on the 1997 Prairie Warbler Survey Along the Southeastern Shoreline of Georgian Bay, Ontario. Ontario Natural Heritage Information Centre, Ontario.
  • Lambert, A.B. and R.B.H. Smith. 1984. The status and distribution of the Prairie Warbler in Ontario. Ontario Birds 2:99-115.
  • Sutherland, D.A. and C.G. Harris. 2007. Prairie Warbler. pp. 492-493 in: Atlas of the Breeding Birds of Ontario, 2001-2005. Cadman, M.D., D.A. Sutherland, G.G. Beck, D. Lepage and A.R. Couturier, Eds. Bird Studies Canada, Environment Canada, Ontario Field Ornithologists, Ontario Ministry of Natural Resources, and Ontario Nature, Toronto, Ontario.