Population status

Ring-billed Gull
(Larus delawarensis)

The Ring-billed Gull breeds widely across Canada, where a large portion of its population is well covered by the Breeding Bird Survey (BBS). Results from the BBS suggest that both the Canadian and continental populations have exhibited large increases in abundance since about 1970. However, there is regional variation in the results, with the central and western Bird Conservation Regions (BCRs) showing smaller increases or even declines, and the eastern BCRs showing strong increases (all BCRs for which there are reasonably reliable BBS results in Canada are shown below). The species has also expanded its range to the north and west (Sirois et al. 1995, Pollet et al. 2012). However, although the abundance in Canada remains well above 1970s levels, censuses of colonies in the Great Lakes report a 26% decline in the abundance of Ring-billed Gulls between 1999 and 2009. Declines have also been observed in the large St. Lawrence River and Estuary population (Cotter et al. 2012). These declines are partly attributable to direct management of populations due to conflicts with humans at several locations (Morris et al. 2011, Cotter et al. 2012); see Conservation and Management). The Ring-billed Gull is currently at an acceptable level relative to its national population goal (see BBS Canada graph below).

 

Population goal and acceptable levels of variation

Species/groupGoalLower levelUpper level
Ring-billed GullMean abundance (2008-2012)10th percentile of observed abundance (1970-2012)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 analysis1970-20161.70.63.4
Boreal Taiga Plains Select to view graph of the geographic area: Boreal Taiga Plains 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-20160.9-1.43.1
Prairie Potholes Select to view graph of the geographic area: Prairie Potholes 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-2016-0.6-2.10.9
Boreal Hardwood Transition Select to view graph of the geographic area: Boreal Hardwood Transition 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-20163.20.55.4
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 analysis1970-20166.23.88.8
Atlantic Northern Forest Select to view graph of the geographic area: Atlantic Northern Forest 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-20164.61.47.6
North America Select to view graph of the geographic area: North America 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-20161.80.63
 

British Columbia Coastal Waterbird Survey

Additional information on: British Columbia Coastal Waterbird Survey

Table 2: Population trends by geographic area
Geographic areaTime PeriodAnnual Trend Table 2 - footnote 1 Limits
LowerUpper
British Columbia coast1999-2016-2.1-6.32.2
 

Great Lakes Decadal Colonial Waterbird Census

Additional information on: Great Lakes Decadal Colonial Waterbird Census

Table 3: Population trends by geographic area
Geographic areaTime PeriodAnnual Trend Table 3 - footnote 1 Standard error
LowerUpper
Great Lakes Select to view graph of the geographic area: Great Lakes 1976-2009; Great Lakes Decadal Colonial Waterbird Census1976-2009   
 

References