Population status

California Gull
(Larus californicus)

The California Gull typically nests in colonies on islands in lakes, making it difficult to survey with the roadside Breeding Bird Survey (Winkler 1996). Similarly, because the species forms large flocks in winter, Christmas Bird Counts (CBC) can suffer from counting error. In both cases,  the precision of the trend estimate from both surveys is poor. Despite these limitations, both surveys suggest that the species has increased in abundance since about 1970 in Canada and, for CBC, throughout its range, though the magnitude of the increase is uncertain.

 

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 Intervals Table 1 - footnote3
LowerUpper
Canada Select to view graph of the geographic area: Canada 1970-2012; Breeding Bird Survey (BBS) - Canadian analysis1970-20120.4-3.63.4
 

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
North America Select to view graph of the geographic area: North America 1965-2012; Christmas Bird Count (CBC)1965-20123.72.35.4
Canada Select to view graph of the geographic area: Canada 1965-2012; Christmas Bird Count (CBC)1965-20123.906.9
 

References