Population status

Fox Sparrow
(Passerella iliaca)

The Breeding Bird Survey (BBS) is considered the best source of population data for the Fox Sparrow, although it covers only the extreme southern edge, and some western and eastern sections of the breeding population. Results suggest about an approximate 45% increase in abundance since 1970. The Christmas Bird Count (CBC) provides good coverage of the wintering range of this species. CBC results for North America suggests little overall change in the continental population, though this includes birds breeding in both Canada and the United States. CBC results for Canada reflect the small over-wintering populations in British Columbia and southern Ontario and suggest an increase in those regions. Relying mainly on the national BBS, the Fox Sparrow is best assessed as having shown a moderate increase in Canada. The CBC results provide support for that assessment as they show no suggestion of a population decrease at the national level, and suggest an increase in two Canadian regions. Considering the results of both surveys, this assessment is considered to be of medium reliability. The Fox Sparrow is at an acceptable level relative to its national population goal (see Canada BBS graph below).

 

Population goal and acceptable levels of variation

Species/groupGoalLower levelUpper level
Fox SparrowMean abundance (2008-2012)Mean long-term abundance (1970-2012) 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 analysis1970-20160.8-0.71.8
North America Select to view graph of the geographic area: North America 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-20160.3-0.50.9
 

Picture of logo Christmas Bird Count (CBC)

Additional information on: Christmas Bird Count (CBC)

Table 2: Population trends by geographic area
Geographic areaTime PeriodAnnual Trend Table 2 - footnote 1 Limits
LowerUpper
Canada Select to view graph of the geographic area: Canada 1970-2016; Christmas Bird Count (CBC)1970-20162.61.43.85
North America Select to view graph of the geographic area: North America 1970-2016; Christmas Bird Count (CBC)1970-2016-0.2-0.60.16
 

References