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 has not been quantified, but it is not believed to 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.
Global population size is unknown owing to recent taxonomic splits. The European population is estimated at 54,100-87,500 pairs, which equates to 108,000-175,000 mature individuals (BirdLife International 2015).
The population is estimated to be increasing (BirdLife International 2015).
This species can be found in eastern Europe, the Middle East, north-west Africa and central Asia. It is resident in much of the Black Sea and Caspian Sea. It also seasonally breeds from the Black Sea, across the north of the Caspian Sea to eastern Kazakhstan, and on the central Asian steppes. Wintering grounds include the coast of south-west Asia (breeders from the steppes), the north-east coast of Africa, and around the Arabian Peninsula up to north-west India.
Behaviour This species is fully migratory, though some colonies around the Black and Caspian Sea may be resident (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 (Burger et al. 2018).
Habitat Breeding During the breeding season the species nests near lakes surrounded by reedbeds (Olsen and Larsson 2003) in steppe and semi-desert (Central Asia) (del Hoyo et al. 1996), reservoirs, rivers, 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). In these coastal habitat it forages in intertidal zones (del Hoyo et al. 1996) and in brackish coastal marshes (Snow and Perrins 1998). Non-breeding Outside of 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)), 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).
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).
Reported that colonies in the east of the range are frequently raided for eggs and the species is hunted in the Ukraine (Rudenko 2006, Burger et al. 2018). Has previously been culled to protect other Larus species, however this has not been recorded recently. Numerous small oil spills have been reported to cause mortality in the species, for example in Azerbaijan (Burger et al. 2018), though this appears to have minimal impact on the population trend.
Conservation Actions Underway
The following information refers to the species's European range only: The species is covered under the African Eurasian Waterbird Agreement. Within the EU it is listed on Annex II of the Birds Directive. There are 73 Important Bird Areas where this species occurs in Europe. In the EU there are 354 Special Protection Areas for this species.
Conservation Actions Proposed
The following information refers to the species's European range only: Management of key breeding and feeding sites to reduce human disturbance and habitat destruction.
Text account compilers
Ekstrom, J., Ashpole, J, Butchart, S., Malpas, L., Stuart, A., Calvert, R.
BirdLife International (2023) Species factsheet: Larus cachinnans. Downloaded from http://datazone.birdlife.org/species/factsheet/caspian-gull-larus-cachinnans on 30/09/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 30/09/2023.