Lava Gull (Larus fuliginosus) - BirdLife species factsheet

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VU	Lava Gull Larus fuliginosus

2010 IUCN Red List Category (as evaluated by BirdLife International - the official Red List Authority for birds for IUCN): Vulnerable

Justification This poorly known species is considered Vulnerable because it has a very small population. Numbers are assumed to be stable, although there are a number of potential threats, which may be having an impact.

Family/Sub-family Laridae

Species name author Gould, 1841

Taxonomic source(s) SACC (2005 + updates), Sibley and Monroe (1990, 1993), Stotz et al. (1996)

Identification 53 cm. Unmistakable, all-dark gull. Overall dark ashy-grey, darkest on wings and palest on belly and vent. Noticeably darker hood with white eyelids. Black bare parts, red inside of mouth. Immature browner.

Population estimate	Population trend	Range estimate (breeding/resident)	Country endemic?
600 - 800	stable	1,480 km²	Yes

Range & population Larus fuliginosus breeds only in the Galápagos Islands, Ecuador. It is widespread throughout the archipelago, with possibly the most dense populations found at Puerto Ayora (Santa Cruz)^3,5, Puerto Baquerizo Moreno (San Cristóbal) and Puerto Villamil (Isabela)⁵. In 1963, a survey of 56 km of coastline on the south and east of Santa Cruz found eight territories, which was extrapolated over the remaining coastline in the archipelago to give an estimate of 300-400 pairs. This was considered an overestimate. It has been suggested that the tiny population is probably a consequence of its confinement to linear feeding grounds of restricted range, which provide a limited food supply for much of the year⁴.

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: It nests solitarily in sheltered places near lagoons, pools and other calm water, usually close to the sea⁴. It is a scavenger, with local concentrations of birds in areas of high food availability, such as harbours, and will associate with boats¹. However, it also takes seabird eggs, juvenile marine iguana Amblyrhynchus cristatus, small fish and crustaceans⁴. It nests in scrapes on sandy beaches or low outcrops close to water, and lays two eggs¹. Territories are large, and adults are extremely wary, leaving the nest when a potential intruder is as far as 1 km away⁴.

Threats Potential threats (applicable to many of the Galápagos seabirds) include predation and disturbance by introduced mammals such as feral cats, rats and dogs^2,5.

Conservation measures underway Although much of the island archipelago is protected in the Galápagos National Park, the greatest densities of this species may occur in the three main ports, and these urban areas are not part of the national park⁵. The islands were declared a World Heritage Site in 1979.

Conservation measures proposed Develop and use methodologies for accurate population censuses and long-term monitoring⁵. Control populations of introduced mammals.

References 1. Burger and Gochfeld (1996). 2. Cepeda and Cruz (1994). 3. Jackson (1985). 4. Snow and Snow (1969). 5. H. Vargas and F. Cruz in litt. (2000).

Text account compilers Phil Benstead (BirdLife International), Rachel McClellan (BirdLife International), John Pilgrim (BirdLife International), Andy Symes (BirdLife International)

Contributors Francisco Cruz, Hernan Vargas (Charles Darwin Research Station)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Rob Calvert (BirdLife International)

Recommended citation BirdLife International (2010) Species factsheet: Larus fuliginosus. Downloaded from http://www.birdlife.org on 30/7/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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