The grey gull, also known as garuma gull (''Leucophaeus modestus'') is a medium-sized

gull Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century ...

native to

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

. Unusual among gulls, it breeds inland in the extremely dry

Atacama Desert The Atacama Desert ( es, Desierto de Atacama) is a desert plateau in South America covering a 1,600 km (990 mi) strip of land on the Pacific coast, west of the Andes Mountains. The Atacama Desert is the driest nonpolar desert in th ...

in northern

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

, although it is present as a non-breeding bird along much of the Pacific coast of South America.

Description

The sexes are similar in grey gulls. Adults grow to a length of about and weigh some . The head is white in summer but brownish-grey in winter. The body and wings are grey with the dorsal surface rather darker than the ventral region. The

flight feathers Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tai ...

are black and the inner primaries and the secondaries have white tips, visible in flight. The tail has a band of black with a white trailing edge. The legs and beak are black and the iris is brown.Josep del Hoyo, Andrew Elliott, Jordi Sargatal (Eds.): ''Handbook of the Birds of the World''. Volume 3: Hoatzin to Auks. Lynx Edicions 1996, , p. 602 The call is similar to that of the

laughing gull The laughing gull (''Leucophaeus atricilla'') is a medium-sized gull of North and South America. Named for its laugh-like call, it is an opportunistic omnivore and scavenger. It breeds in large colonies mostly along the Atlantic coast of North Am ...

(''Leucophaeus atricilla'').

Distribution

The grey gull breeds inland in the

in northern Chile. Its non-breeding range includes Costa Rica, Colombia, Ecuador, Peru and Chile, and it has been recorded in the Falkland Islands, South Georgia and the South Sandwich Islands. It is a vagrant to Panama.

Behaviour

Breeding

For many years, it was a mystery as to where this bird breeds because no coastal colonies had been identified. However, in 1945, it was discovered that it bred in the

in the interior of Chile. This hot and arid environment has few

predators Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

and may be relatively safe for the breeding gulls. The site chosen for the nest, a scrape in the sand and often near rocks, is a waterless region some from the coast. Once the eggs hatch, the parents take it in turn to make the round trip to the sea to bring food and water to their offspring. The humidity, wind speed, air and surface temperatures vary widely on a daily basis and the gull has to use various thermo-regulatory mechanisms when nesting to maintain its body temperature and that of its eggs and chicks within acceptable limits. In the hottest part of the day the parent bird stands over its nest to prevent the eggs or chicks overheating. Its chief predator is the

turkey vulture The turkey vulture (''Cathartes aura'') is the most widespread of the New World vultures. One of three species in the genus '' Cathartes'' of the family Cathartidae, the turkey vulture ranges from southern Canada to the southernmost tip of Sout ...

(''Cathartes aura'') and when threatened, the incubating parent sometimes leaves the nest temporarily, and when this happens the eggs need to have impervious shells in order to avoid losing too much water through evaporation. In fact, the evaporative loss from the eggs is found to be about one third of that which occurs in

Heermann's gull Heermann's gull (''Larus heermanni'') is a gull resident in the United States, Mexico and extreme southwestern British Columbia, nearly all nesting on Isla Rasa in the Gulf of California. They are usually found near shores or well out to sea, very ...

(''Larus heermanni''), another desert nesting species.

Feeding

The typical habitat of the grey gull is sandy beaches and mudflats along the western coasts of South America where it probes with its beak in the sediment for invertebrate prey, particularly

mole crab Hippoidea is a superfamily of decapod crustaceans known as sand crabs or mole crabs. Ecology Hippoids are adapted to burrowing into sandy beaches, a habit they share with raninid crabs, and the parallel evolution of the two groups is strikin ...

s. It also eats fish and ragworms, scavenges for offal and sometimes follows fishing boats.

Status

The grey gull has a restricted inland breeding range and a limited wintering range along the coasts of Ecuador, Peru and Chile. The population trend is believed to be downwards. However, the total number of birds is sufficiently large to justify listing the grey gull as being of "

least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

" rather than including it in a more threatened category.

References

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grey gull The grey gull, also known as garuma gull (''Leucophaeus modestus'') is a medium-sized gull native to South America. Unusual among gulls, it breeds inland in the extremely dry Atacama Desert in northern Chile, although it is present as a non-bree ...

Birds of Chile

Taxobox binomials not recognized by IUCN Taxa named by Johann Jakob von Tschudi