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Lava Gull Larus fuliginosus

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.

Taxonomic source(s)
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.
SACC. 2006. A classification of the bird species of South America. Available at: #http://www.museum.lsu.edu/~Remsen/SACCBaseline.html#.

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.

Distribution and 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) (Jackson 1985, H. Vargas and F. Cruz in litt. 2000), Puerto Baquerizo Moreno (San Cristóbal) and Puerto Villamil (Isabela) (H. Vargas and F. Cruz in litt. 2000). 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 has been considered an overestimate, and an estimate by Aguirre (2007) determined only 81 individuals in the largest population, on Santa Cruz Island. If extrapolated, this would produce a total population of only 243 individuals (D. Wiedenfeld in litt. 2012). 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 year (Snow and Snow 1969).

Population justification
Snow and Snow (1969) estimated 600-800 mature individuals which Wetlands International (2002) interpreted to equate to 900-1,200 individuals. This may be an overestimate (Aguirre 2007, D. Wiedenfeld in litt. 2012).

Trend justification
Numbers are assumed to be stable although there are a number of potential threats which may be having an impact

Ecology
It nests solitarily in sheltered places near lagoons, pools and other calm water, usually close to the sea (Snow and Snow 1969). It is a scavenger, with local concentrations of birds in areas of high food availability, such as harbours, and will associate with boats (Burger and Gochfeld 1996). However, it also takes seabird eggs, juvenile marine iguana Amblyrhynchus cristatus, small fish and crustaceans (Snow and Snow 1969). It nests in scrapes on sandy beaches or low outcrops close to water, and lays two eggs (Burger and Gochfeld 1996). Territories are large (Snow and Snow 1969).

Threats
Lava Gulls are threatened by fishing activities, such as being caught on hooks as bycatch and direct persecution by fishermen, and from feeding on refuse (Wiedenfeld and Jiménez 2008). Potential threats (applicable to many of the Galápagos seabirds) include predation and disturbance by introduced mammals such as feral cats, rats and dogs (Cepeda and Cruz 1994, H. Vargas and F. Cruz in litt. 2000).

Conservation Actions 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  (Wiedenfeld 2006), and these urban areas are not part of the national park (H. Vargas and F. Cruz in litt. 2000). The islands were declared a World Heritage Site in 1979. Conservation Actions Proposed
Develop and use methodologies for accurate population censuses and long-term monitoring (H. Vargas and F. Cruz in litt. 2000). Identify nesting areas and control populations of introduced mammals.

References
Aguirre, D. 2007. Aspectos etológicos, influencia antropogénica y distribución de la Gaviota de Lava (Larus fuliginosus), una especie endémica del archipiélago de Galápagos. Tesis de Licenciatura. . Universidad Central de Ecuador..

Burger, J.; Gochfeld, M. 1996. Laridae (Gulls). In: del Hoyo, J.; Elliott, A.; Sargatal, J. (ed.), Handbook of the birds of the world, pp. 572-623. Lynx Edicions, Barcelona, Spain.

Cepeda, F.; Cruz, J. B. 1994. Status and management of seabirds on the Galápagos Islands, Ecuador. In: Nettleship, D.N.; Burger, J.; Gochfeld, M. (ed.), Seabirds on islands: threats, case studies and action plans, pp. 268-278. BirdLife International, Cambridge, U.K.

Jackson, M. H. 1985. Galapagos: a natural history guide. Calgary University Press, Calgary, Canada.

Snow, B. K.; Snow, D. W. 1969. Observations on the Lava Gull Larus fuliginosus. Ibis 111: 30-35.

Wetlands International. 2002. Waterbird population estimates. Wetlands International, Wageningen, Netherlands.

Wiedenfeld, D. A. 2006. Aves, the Galápagos Islands, Ecuador. Check List 2: 1-27.

Wiedenfeld, D. A.; Jiménez-Uzcátegui, G. A. 2008. Critical problems for bird conservation in the Galápagos Islands. Cotinga: 22-27.

Further web sources of information
Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Benstead, P., McClellan, R., Pilgrim, J., Sharpe, C J, Symes, A.

Contributors
Cruz, F., Vargas, H., Wiedenfeld, D.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Larus fuliginosus. Downloaded from http://www.birdlife.org on 30/09/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 30/09/2014.

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.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Lava gull (Larus fuliginosus) 0

Key facts
Current IUCN Red List category Vulnerable
Family Laridae (Gulls, Terns, Skimmers)
Species name author Gould, 1841
Population size 600-800 mature individuals
Population trend Increasing
Distribution size (breeding/resident) 1,480 km2
Country endemic? Yes
Links to further information
- Additional Information on this species