Coastal Resource Information System

Gulls

Gulls are abundant and widely distributed throughout the study area at all times of the year. They occur mainly on marine waters, rocky islets, spits and beaches, but only the Glaucous-winged Gull breeds locally. Gulls are moderate to highly vulnerable to oil on water (King and Sanger 1979). In addition, Gulls scavenge the oil soaked carcasses of mammals and other birds, thereby promoting the ingestion of oil. Mortality from fouling of plumage and ingestion of oil can be high (Burger 1992).

Adult Glaucous-winged Gulls are at some risk from oil on the water, but oil on the shoreline of islands used by breeding birds would cause relatively few problems because the adults fly directly to and from their nests. All nests are situated above the splash zone. Juvenile Gulls leaving the natal colony would likely contact oil on the shoreline because they enter the water before flying. Non-breeding adults that roost on rocks in the splash zone would also be highly vulnerable to oil.

Breeding Gulls are likely vulnerable to disturbances caused by nearby oil cleanup activities from May through August. Disturbance during the laying and incubation periods (May till July) would have the most serious impacts, leading to possible nest abandonment. Gull nests are less vulnerable to predation that those of Cormorants or Oystercatchers. Outside of the breeding season, Gulls are not likely to be vulnerable to oil cleanup because they can move to other areas if disturbed.

Gull species present in Coastal BC:

• Glaucous-winged Gull
• Mew Gull
• California Gull

Detailed species reports from the British Columbia Species and Ecosystem Explorer are available by following the above links.

These species are also breifly described below in exerpts from: The Birds of British Columbia, Vol. 2, Nonpasserines: Diurnal Birds of Prey through Woodpeckers by R. Wayne Campbell, Neil K. Dawe, Ian McTaggart-Cowan, John M. Cooper, Gary W. Kaiser and Michael C.E. McNall.

Glaucous-winged Gull

Widely distributed, they prefer nearshore areas, but regularly visit fishing vessels well offshore and may be partially pelagic in some seasons. Glaucous-winged Gulls occur in extremely large numbers in bays, harbours, estuaries and rivers where Pacific Herring, Salmon and Eulachon are found. They are very gregarious and often congregate with other marine birds. (Photo credit: Canadian Wildlife Service).

Mew Gull

The Mew Gull is widely distributed in coastal British Columbia. It frequents a variety of habitats including bays, estuaries, surge narrows, beaches, mudflats, harbours and sewage outlets.

California Gull

The California Gull occurs widely on the British Columbia coast. It frequents beaches, bays, estuaries, lagoons, agricultural fields, airports, garbage dumps, sewage outlets and less often, brackish sloughs and freshwater lakes. In autumn the California Gull is the most abundant gull off of the BC coast. It roosts at night in large flocks on sheltered bodies of water along the coast including bays, inlets, rivers, islands, and log booms. It breeds along the inner and outer coastal waters of BC from Race Rocks off southern Vancouver Island, north to Zayas Island, including the Queen Charlotte Islands. They prefer sites on small offshore islands less than 25m in height and ranging in size from 2 to 10 ha. All the major colonies are on islands that are less than 25 ha in size and 100m above sea level.