BC Conservation Data Centre: Conservation Status Report
Larus californicus
California Gull
| Scientific Name: | Larus californicus |
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| English Name: | California Gull |
| Provincial Status Summary | |
| Status: | S1B,SNRN |
| Date Status Assigned: | March 25, 2022 |
| Date Last Reviewed: | March 25, 2022 |
| Reasons: | Small breeding population with restricted range and was formerly expanding but growth has appeared to stablize. |
| Range | |
| Range Extent: | E = 5,000-20,000 square km |
| Range Extent Comments: | Breeding is restricted to between two and six locations in the central and southern interior. Siddle (2015) notes two breeding locations confirmed during the BC Breeding Bird Atlas and an additional two were probable breeding locations. Campell et al .1990 documented the change in status of the species from a transient in small numbers prior to the 1960s to the situation now where most of the prairie breeding population of the species passes through British Columbia in late summer. Breeding in BC was first noted in the 1970s. |
| Area of Occupancy (km2): | BC = 2-5 |
| Area of Occupancy Comments: | Breeding sites are very tiny and highly restricted. The Breeding Bird Atlas documented two with a possible two more found during the atlas period (Siddle 2015) but these require confirmation. |
| Occurrences & Population | |
| Number of Occurrences: | A = 1 - 5 |
| Comments: | Known or suspected to breed at only four sites in British Columbia. Grant (Whiskey) Island in Okanagan Lake, the Osoyoos Sewage Lagoon and possibly at Harrison and Lillooett Lake (Siddle 2015). Ellis Island in Fraser Lake, Gravel Island on the Quesnel River, and Shuswap Lake near Salmon Arm (R.W. Campbell, pers. comm.) have been sites in the past, but breeding was not detected during the atlas field work. Those sites should be monitored for breeding. Recent sightings on Harrison Lake and Lillooet Lake during the breeding season should be investigated. |
| Number of Occurrences with Good Viability / Ecological Integrity: | Rank Factor not assessed |
| Number of Occurrences Appropriately Protected & Managed: | B = 1 - 3 |
| Comments: | Grant (Whiskey) Island in Okanagan Lake and Ellis Island in Fraser Lake are both protected. |
| Population Size: | AB = 1 - 250 individuals |
| Comments: | The breeding population is estimated at 25 - 100 pairs (R.W. Campbell, pers. comm.). Grant (Whiskey) Island population was estimated at 17 pairs in 1986 (Campbell et al. 1990b) but not counted during the breeding bird atlas (Siddle 2015), the Osoyoos Sewage Lagoon site had 4-5 pairs during the Atlas period (Siddle 2015). Migrants that breed outside British Columbia occur in the tens of thoudands on the west coast in late summer and autumn (e.g. 11,000 at Port Renfrew October 2016 [https://ebird.org/canada/checklist/S32103595]). |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | BD = High - low |
| Comments: | Nesting colonies are susceptible to human disturbance and the very small populations are also subject to random environmental fluctuations. |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | G = Relatively Stable (<=10% change) |
| Comments: | Formerly the breeding population was increasing and expanding its range, but it has apparently stablized. |
| Long-Term Trend: | HI = Increase of >10% |
| Comments: | For the breeding population, increases from historical values are noted. The increase is much higher for the migrant population, which has increased several orders of magnitude since the 1950's (Campbell et al 1990b). |
| Other Factors | |
| Intrinsic Vulnerability: | Rank Factor not assessed |
| Environmental Specificity: | Rank Factor not assessed |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | |
| Inventory Needs: | Nesting (known and potential) colonies should be monitored periodically to determine population trends. Major staging and moulting areas of migrant populations should be located and mapped. |
| Stewardship | |
| Protection: | |
| Management: | Maintain signposts warning against human disturbance of nesting colonies. Training of inventory crews to minimize disturbance is important. Determine taxonomic status of the California Gulls breeding in the province so the subspecies will be known with certainty. |
| Version | |
| Author: | Ramsay, L.R. and B. Niedzielski and S. Cannings updated by D.F.Fraser (2020, 2022) |
| Date: | January 12, 2022 |
| References | |
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Campbell, R.W., N.K. Dawe, I. McTaggart-Cowan, et al. 1990b. The Birds of British Columbia Vol. 2: Nonpasserines: Diurnal Birds of Prey through Woodpeckers. Royal British Columbia Museum, Victoria, BC.
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Cannings, R.A., R.J. Cannings, and S.G. Cannings. 1987. Birds of the Okanagan Valley, B.C. Royal B.C. Mus., Victoria, BC. 420pp.
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Cannings, R.J. 1998. The Birds of British Columbia - a taxonomic catalogue. B.C. Minist. Environ., Lands and Parks, Wildl. Branch, Victoria, Wildl. Bull. B-86. 266pp.
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Godfrey, W.E. 1986. The Birds of Canada, rev. ed. Natl. Mus. Can., Ottawa, ON. 595pp.
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Jehl, J.R. Jr., 1987. Geographic variation and evolution in the California Gull (Larus californicus). Auk 104:421-428.
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Siddle, C.R. 2015. California Gull in: Davidson, P.J.A., R.J. Cannings, A.R. Couturier, D. Lepage, and C.M. Di Corrado (eds.). The atlas of the breeding birds of British Columbia, 2008-2012. Bird Studies Canada. Delta, BC. Available: http://www.birdatlas.bc.ca/accounts/speciesaccount.jsp?sp=CAGU&lang=en.
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Vermeer, K. 1970. Breeding biology of California and Ring-Billed Gulls. Can. Wild. Serv. Rep. Ser. No. 12, Ottawa, ON. 52pp.
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Winkler, D.W. 1996. California Gull (Larus californicus). in A. Poole, and F. Gill, eds. The Birds of North America, No. 259. Acad. Nat. Sci., Philadelphia, PA, and Am. Ornithol. Union, Washington, DC. 28pp.
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Please visit the website Conservation Status Ranks for information on how the CDC determines conservation status ranks. For global conservation status reports and ranks, please visit the NatureServe website http://www.natureserve.org/.
Suggested Citation:
B.C. Conservation Data Centre. 2022. Conservation Status Report: Larus californicus. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 16, 2026).