WCS Argentina

Gulls and Terns

Three species of gulls and three species of terns are regular breeders on the coast of Patagonia. The most abundant gull is the kelp gull, which is widely distributed throughout the region and has shown large increases in population numbers. Olrog’s gull on the other hand is relatively rare and breeds in a handful of small colonies on the southern shore of the Province of Buenos Aires and Golfo SanJorge in Chubut on the coast of Argentina. This is the only threatened gull in the southern cone. The dolphin gull breeds in compact colonies usually associated with breeding colonies of marine birds and mammals. The South American tern is the most abundant species of tern and forms large breeding colonies onshore, often numbering several thousand pairs. Royal and cayenne terns often breed in small compact colonies with their nests intermingled.

Conservation Challenges

The kelp gull provides special management challenges on the coast of Patagonia. This successful seabird is widely distributed in the region, has an enormously varied diet and is quick to learn new feeding behaviors. Kelp gulls can predate eggs and chicks of other seabirds and waterfowl, including threatened species such as the red-legged cormorant and white-headed steamer duck, and some have even learned to feed off the skin of live southern right whales. Kelp gulls regularly use garbage dumps and take advantage of discards generated by trawl fisheries, and their populations have been increasing throughout the region. The main breeding grounds of the threatened Olrog’s gull are subject to growing habitat modification and disturbance by human development.

Conservation Approach

WCS provides assistance for the creation and strengthening of coastal protected areas to ensure that gulls and terns on the coast of Patagonia are effectively protected especially Olrog’s gull and all species of terns. We gather research information for the conservation of this group of seabirds and for the management of problem species such as the kelp gull, and transfer of this information to management. Our efforts are helping to build a strong local constituency for the conservation of these species and the marine environments they inhabit.


Ensure the conservation of gulls and terns as valuable components of Patagonia’s coastal biodiversity.


WCS monitors populations of gulls and terns on the coast. Our research contributes to the spatial planning of marine protected areas and to the reduction of conflicts with human activities, particularly in relation to the threatened Olrog’s gull. Knowledge we provide on the way kelp gulls use fish waste and other human related food sources is employed by government authorities to manage fisheries and urban waste in Patagonia. We are also providing management recommendations to reduce negative interactions between gulls and terns and other species (especially kelp gulls and other seabirds and coastal wildlife). Our outreach activities serve to increase awareness of the value of coastal biodiversity.


Olrog’s gull has a limited range and specialized feeding behaviors that make it vulnerable to coastal habitat degradation and pollution. Human disturbance of breeding colonies are also a concern. All tern species are vulnerable to fishing activities that reduce food supply, and are highly sensitive to disturbance of their breeding colonies. If disrupted on the nest, terns can abandon eggs and chicks and the entire breeding season is lost.


WCS participation in the creation of coastal protected areas in Patagonia has resulted in protection for of large proportion of breeding colonies of gulls and terns.


WCS Argentina
Amenabar 1595 piso 2 oficina 19, C1426AKC CABA

Key Staff

Pablo Yorio
Coastal Argentina Program Seabirds

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