Justification of Red List Category
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 appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very 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.
The global population size is unknown owing to recent taxonomic splits. The European population is estimated at 409,000-534,000 pairs, which equates to 819,000-1,070,000 mature individuals (BirdLife International 2015).
The overall population trend is increasing, although some populations have stable or unknown trends (Wetlands International 2015). The European population is estimated to be increasing (BirdLife International 2015).
This species can be found in Europe, the Middle East and north Africa. It is resident in much of southern Europe, on the coasts of the Mediterranean, Black Sea and Caspian Sea, on the Azores and Madeira, Portugal, and on the Canary Islands. Spain. Wintering grounds include the coast of south-west Asia (breeders from the steppes), most of the European coast up to Denmark and the coast of Africa from Western Sahara through to the eastern Mediterranean (del Hoyo et al. 1996).
Behaviour Populations may be dispersive or sedentary (del Hoyo et al. 1996). Post-breeding movements to wintering areas occur from July to November, with the return migration occurring from mid-February to mid-June (Olsen and Larsson 2003). The species breeds from mid-March to April (del Hoyo et al. 1996, Snow and Perrins 1998), although the exact timing varies geographically (Olsen and Larsson 2003). It breeds colonially in groups of up to 8,000 pairs, and may nest in monospecific clusters within mixed-species colonies (del Hoyo et al. 1996). Outside of the breeding season the species remains gregarious, congregating around ports, harbours and refuse dumps (le Grand et al. 1984).
Habitat Breeding During the breeding season the species nests near lakes surrounded by reedbeds (Olsen and Larsson 2003), pastures (Madeira) (le Grand et al. 1984), reservoirs, rivers (de Juana 1984), and on grassy or shrubby river islands (del Hoyo et al. 1996), also forming colonies on sea cliffs (de Juana 1984), rocky and sandy offshore islands, rocky coasts (del Hoyo et al. 1996, Snow and Perrins 1998), sandy beaches, spits (del Hoyo et al. 1996), sand-dunes, and salt-pans (Snow and Perrins 1998), and foraging in intertidal zones (del Hoyo et al. 1996) and in brackish coastal marshes (Snow and Perrins 1998). Non-breeding Outside the breeding season the species is more common along the coast (e.g. at harbours and ports) and in other marine habitats (though seldom far from land). During this season it also forages in cultivated fields (del Hoyo et al. 1996, Snow and Perrins 1998, Olsen and Larsson 2003) and along rivers, and is especially common at refuse dumps (del Hoyo et al. 1996, Snow and Perrins 1998).
Diet Its diet consists of fish, invertebrates (including insects, molluscs [Olsen and Larsson 2003] and crabs [Munilla 1997]), reptiles, small mammals (e.g. voles [del Hoyo et al. 1996] and ground squirrels [Snow and Perrins 1998]), refuse, offal, and bird eggs and chicks (del Hoyo et al. 1996), e.g. of petrels and shearwaters (le Grand et al. 1984).
Breeding site The nest is constructed of nearby vegetation, feathers, debris and old carcasses, and is preferably positioned close to or under bushes (del Hoyo et al. 1996), or on rocky and sandy islands, beaches, spits, sea cliffs, grassy or shrubby river islands (del Hoyo et al. 1996), and occasionally on high ground hundreds of metres from water (del Hoyo et al. 1996). The species breeds colonially in monospecific or mixed-species groups, with pairs usually nesting a few metres apart (del Hoyo et al. 1996).
Egg collection is often carried out by local communities (James 1984, de Juana 1984, del Hoyo et al. 2018), primarily occurring in unprotected colonies and with little impact on population size. Culling occurs in a number of locations throughout the range for various reasons including to reduce conflict with people and for the conservation of other bird species (e.g. White-faced Storm-petrel Pelagodroma marina in Macronesia) (del Hoyo et al. 2018, Bosch et al. 2000).
Conservation Actions Underway
The following information refers to the species's European range only: There is a single Important Bird Area identified for this species in Turkey. In the EU there are two Special Protection Areas, in Spain.
Conservation Actions Proposed
The following information refers to the species's European range only: No specific conservation measures are proposed.
Text account compilers
Taylor, J., Butchart, S., Malpas, L., Stuart, A., Martin, R., Ashpole, J, Calvert, R., Everest, J., Ekstrom, J., Symes, A., Elliott, N., Hermes, C.
BirdLife International (2021) Species factsheet: Larus michahellis. Downloaded from http://www.birdlife.org on 02/12/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 02/12/2021.