Species

Justification
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Taxonomic source(s)
AOU. 1998. Check-list of North American birds. American Ornithologists' Union, Washington, D.C.
Cramp, S.; Perrins, C. M. 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
Dowsett, R. J.; Forbes-Watson, A. D. 1993. Checklist of birds of the Afrotropical and Malagasy regions. Tauraco Press, Li
SACC. 2006. A classification of the bird species of South America. Available at: http://www.museum.lsu.edu/~Remsen/SACCBaseline.html.
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.
Stotz, D. F.; Fitzpatrick, J. W.; Parker, T. A.; Moskovits, D. K. 1996. Neotropical birds: ecology and conservation. University of Chicago Press, Chicago.

Taxonomic note
Larus cachinnans (Sibley and Monroe 1990, 1993) has been split into L. cachinnans and L. michahellis; L. armenicus (Sibley and Monroe 1990, 1993; AERC TAC) has been lumped into L. michahellis. These changes to the BirdLife checklist follow examination by the BirdLife Taxonomic Working Group (BTWG) of a recent review of large white-headed gulls in the Holarctic by Collinson et al. (2008) and associated literature referred to therein. The following species level treatment, shown with subspecific placements, has been adopted by the BTWG: L. fuscus (with intermedius, graellsii, heuglini, taimyrensis and barabensis); L. argentatus (with argenteus, smithsonianus, vegae and mongolicus); L. michahellis (with atlantis and armenicus) and L. cachinnans. This treatment is based on evidence of sympatry, and morphological and behavioural differences, but rejects further splits derived from phylogentic analyses based on mtDNA because Collinson et al. (2008) admit that (1) mtDNA lineages can disappear by random events, resulting in misplacements and displacements in phylogenies, and (2) hybridisation, which seems very widespread in these white-headed gulls, can result in "adoption" of mtDNA sequences by another taxon, completely obscuring the real situation. Collinson et al. (2008) explicitly state "these complications do not just make gull phylogenies difficult: they may cause entirely false conclusions to be drawn about species boundaries… it must be recognised that splits or lumps based solely on mtDNA cannot be regarded as robust". While proposed splits not adopted here are not based solely on mtDNA, the morphological evidence presented is not conclusive, taxa are only diagnosable in some cases and there is hybridisation between them.

Distribution and population
The Herring Gull breeds in most of Canada and Alaska, as well as the north-east USA, on the northern coastline of Europe including inland Iceland, Ireland, Scandinavia and the United Kingdom, and in the north of Russia from the centre to its eastern tip. Some populations winter further south, being found in much of the USA, Mexico and Central America, on the northern coasts of Spain and France, in much of Japan and on the south-eastern coast of China (del Hoyo et al. 1996).

Population justification
The population is estimated to number 2.7-5.7 million individuals, including totals for Larus heuglini.

Trend justification
The overall population trend is uncertain, as some populations are decreasing, while others are increasing or have unknown trends (Wetlands International 2006). This species has undergone a small or statistically insignificant decrease over the last 40 years in North America (data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007).

Ecology
Behaviour Northern breeding populations of this species are migratory (del Hoyo et al. 1996) although populations in the south are nomadic or completely non-migratory (Flint et al. 1984). The species breeds between mid-April and late-June (Flint et al. 1984, del Hoyo et al. 1996) in colonies of up to several thousand pairs, occasionally nesting solitarily or as single pairs on the edge of other seabird colonies (del Hoyo et al. 1996). Outside of the breeding season the species is highly gregarious and gathers in large flocks in favoured sites (Richards 1990, Snow and Perrins 1998). Individuals show foraging site fidelity (Shamoun-Baranes and van Loon 2006). Habitat The species inhabits coastal and near-coastal areas (del Hoyo et al. 1996) but may also forage inland on large lakes and reservoirs, fields and refuse dumps (del Hoyo et al. 1996). It has no specific breeding habitat (del Hoyo et al. 1996) but may show a preference for rocky shores with cliffs, outlying stacks or islets (del Hoyo et al. 1996, Snow and Perrins 1998), otherwise nesting on rocky and grassy islands, sandy beaches (del Hoyo et al. 1996), dunes (Richards 1990), gravel bars, saltmarshes, rocky outcrops, buildings, claypits (del Hoyo et al. 1996), tundra with reeds or hummocks (Flint et al. 1984), swampy lowlands near lakes and on river islands (Flint et al. 1984). When inland on migration the species also shows a preference for large river valleys (Flint et al. 1984). Diet The species has a highly opportunistic diet and will exploit almost any superabundant source of food (del Hoyo et al. 1996). It takes fish, earthworms, crabs and other marine invertebrates (e.g. molluscs, starfish or marine worms), adult birds, bird eggs and young, rodents, insects (e.g. ants), berries and tubers (e.g. turnips) (del Hoyo et al. 1996). It also scavenges at refuse dumps, fishing wharves and sewage outfall zones and frequently follows fishing boats (del Hoyo et al. 1996, Hiippop and Wurm 2000). Breeding site The nest is a depression in a mound of vegetation (Flint et al. 1984, Richards 1990) placed on the ground, e.g. on a cliff ledge or roof, usually in the shelter of vegetation (del Hoyo et al. 1996). Although Herring Gulls exploit refuse tips and farmland extensively all year round, their breeding distribution is extremely coastal compared to other Larus gulls (other than L. marinus) (Gibbons et al. 1991). Foraging range The species shows increasing foraging distances later in the breeding period (Belant et al. 1993). The feeding range has been variously reported as 35 km (for breeding herring gulls in a Dutch colony) (Spaans 1971), 41 km (in Westphalia, Germany, outside the breeding season) (Sell and Vogt 1986), 50 km (for breeding birds in Morocco) (Witt et al. 1981) and 70 to 100 km (for herring gulls breeding in Denmark) (Klein 1994). Several other studies have reported shorter foraging distances (Andersson 1970, Verbeek 1977, Witt et al. 1981, Sibly and McCleery 1983, Cramp and Simmons 1983, Nogales et al. 1995, Pons and Migot 1995, BirdLife International 2000). Refuse tips are frequently exploited by foraging individuals (Sibly and McCleery 1983, Nogales et al. 1995, Pons and Migot 1995) and so the feeding distribution of some colonies will be determined by location of refuse dumps (BirdLife International 2000). On the basis of a simple density model of birds at sea, it has been estimated that 95% of herring gulls breeding on Terschelling in the Dutch Wadden Sea foraged within 54 km of the colony (BirdLife International 2000). Radio-tracking of four gulls at an inland lake in Ontario indicated extreme specialisation in foraging patterns, with two of the gulls feeding within 1 km whereas two others took extended flights to destinations more than 30 km away (Morris and Black 1980, BirdLife International 2000).

Threats
The species is threatened by coastal oil pollution (Gorski et al. 1977) and is susceptible to avian influenza so may be threatened by future outbreaks of the virus (Melville and Shortridge 2006). Utilisation The species is hunted in Denmark (Bregnballe et al. 2006).

Conservation actions underway
Preventative and control measures are frequently used against this species as it is regarded as a pest and a threat to many other colonial bird species (it usurps habitats and preys upon bird eggs and young), and also to airports (frequently causes collisions) (del Hoyo et al. 1996).

References
Cramp, S.; Simmons, K. E. L. 1983. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic vol. III: waders to gulls. Oxford University Press, Oxford.

Flint, V. E.; Boehme, R. L.; Kostin, Y. V.; Kuznetsov, A. A. 1984. A field guide to birds of the USSR. Princeton University Press, Princeton, New Jersey.

Richards, A. 1990. Seabirds of the northern hemisphere. Dragon's World Ltd, Limpsfield, U.K.

del Hoyo, J.; Elliott, A.; Sargatal, J. 1996. Handbook of the Birds of the World, vol. 3: Hoatzin to Auks. Lynx Edicions, Barcelona, Spain.

Snow, D. W.; Perrins, C. M. 1998. The Birds of the Western Palearctic vol. 1: Non-Passerines. Oxford University Press, Oxford.

Gorski, W.; Jakuczun, B.; Nitecki, C.; Petryna, A. 1977. Investigation of oil pollution on the Polish Baltic coast in 1974-1975. Przeglad Zoologiczny 21(1): 20-23.

BirdLife International. 2000. The Development of Boundary Selection Criteria for the Extension of Breeding Seabird Special Protection Areas into the Marine Environment. OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic. Vlissingen (Flushing).

Bregnballe, T.; Noer, H.; Christensen, T. K.; Clausen, P.; Asferg, T.; Fox, A. D.; Delany, S. 2006. Sustainable hunting of migratory waterbirds: the Danish approach. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 854-860. The Stationary Office, Edinburgh, UK.

Melville, D. S.; Shortridge, K. F. 2006. Migratory waterbirds and avian influenza in the East Asian-Australasian Flyway with particular reference to the 2003-2004 H5N1 outbreak. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 432-438. The Stationary Office, Edinburgh, UK.

Anderson, D.W. 1970. Chlorinated hydrocarbons: their dynamics and eggshell effects in herring gulls and other species. PhD Thesis.

Huppop. O. and Wurm, S. 2000. Effects of winter fishery activities on resting numbers, food and body condition of large gulls Larus argentatus and L-marinus in the south-eastern North Sea. Marine Ecology Progress Series 194: 241-247.

Klein, R. 1994. Silbermöwen Larus argentatus und Weisskopfmöwen Larus cachinnans auf Mülldeponien in Mecklenburg - erste Ergebnisse einer Ringfundanalyse . Vogelwelt 115: 267-286.

Morris, R.D. and Black, J.E. 1980. Radiotelemetry and herring gull foraging patterns. Journal of Field Ornithology 51: 110-118.

Nogales, M., Zonfrillo, B. and Monaghan, P. 1995. Diets of adult and chick herring gulls Larus argentatus argentatus on Ailsa Craig, south-west Scotland. Seabird 17: 56-63.

Pons, J. M., Migot. P. 1995. Life-history strategy of the herring gull: changes in survival and fecundity in a population subjected to various feeding conditions. Journal of Animal Ecology 64: 592-599.

Sell, M., Vogt., T. 1986. [Ecology of Herring Gulls (Larus argentatus) wintering inland: selection and attachment of feeding and roosting sites in the Ruhr region.]. Vogelwarte5 107: 18-3.

Shamoun-Baranes, J., van Loon, E. 2006. Energetic influence on gull flight strategy selection. Journal of Experimental Biology 209(18): 3489-3498.

Sibley, R. M., McCleery, R. H. 1983. Increase in weight of herring gulls while feeding. Journal of Animal Ecology 52: 35-50.

Spaans, A. L. 1971. On the feeding ecology of the Herring Gull Larus argentatus Pont, in the Northern part of the Netherlands. Ardea 59(3-4): 98-188.

Verbeek, N. A. M. 1977. Timing of primary moult in adult Herring Gulls and Lesser Black-backed Gulls. J. Ornithol. 118: 87-92.

Witt, H-H., Crespo, J., de Juana, E. & Varela, J. 1981. Comparative feeding ecology of Audouin’s Gull Larus audouinii and the Herring Gull L. argentatus in the Mediterranean. Ibis 123: 519–526.

Further web sources of information
Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004)

Hear sounds for this species from xeno-canto, the community database of shared bird sounds from around the world.

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

Text account compilers
Butchart, S., Calvert, R., Ekstrom, J., Hatchett, J., Malpas, L.

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

Recommended citation
BirdLife International (2013) Species factsheet: Larus argentatus. Downloaded from http://www.birdlife.org on 20/06/2013. Recommended citation for factsheets for more than one species: BirdLife International (2013) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 20/06/2013.

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

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