Population status

Northwestern Crow
(Corvus caurinus)

Monitoring the Northwestern Crow is complicated by its similarity in appearance and voice to the American Crow. Both the Breeding Bird Survey (BBS) and the Christmas Bird Count (CBC), provide information on its population, although each cover only about one third of the Canadian range. Results from both surveys suggest the population has been relatively stable since 1970 and the Northwestern Crow is considered to be is at an acceptable level relative to its national population goal (see BBS Canada graph). Interestingly, while BBS results from throughout the species' North American range show a similar pattern, with little overall change in the population, the North American CBC results suggest a large decrease over the same time period. The reason for the difference in these continental trends is not clear.

 

Population goal and acceptable levels of variation

Species/groupGoalLower levelUpper level
Northwestern CrowMean 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 analysis1970-20160.3-0.81.5
North America1970-20160.2-11.2
 

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)1970-20160.1-0.60.887
North America Select to view graph of the geographic area: North America 1970-2016; Christmas Bird Count (CBC)1970-2016-2.1-5.20.484
 

References