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 stable, 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.
Although Wetlands International consider the current population trend to be unknown (Delany and Scott 2006), it is suspected to be stable in the absence of evidence for any declines or substantial threats (del Hoyo et al. 1996).
This species can be found in South America on coastal Ecuador and Peru, and from central-eastern and coastal Brazil to Argentina and inland to Paraguay and Santa Fe (Argentina). It is also present throughout much of Africa, both in coastal areas and inland south of the Sahara, including Madagascar (del Hoyo et al. 1996).
Behaviour Most populations of this species are sedentary, although inland breeders will disperse short distances to the coast in the non-breeding season (del Hoyo et al. 1996, Olsen and Larsson 2003). The species breeds colonially, from April-May (before the rains) in Africa, and from early-May in South America (Urban et al. 1986, del Hoyo et al.1996, Olsen and Larsson 2003). It remains fairly gregarious outside of the breeding season, and is typically observed in pairs or small groups of 3-8 individuals, or feeding in large flocks in harbours and at refuse dumps (Langrand 1990, Olsen and Larsson 2003). Habitat Breeding During the breeding season the species inhabits tropical and subtropical coasts, rocky offshore islands, coastal dykes, coastal dunes, estuaries and harbours (Africa), as well as large inland fresh and alkaline lakes (Africa), rivers, salt-pans and marshes (Argentina) (Urban et al. 1986, Martin and Randall 1987, del Hoyo et al. 1996, Olsen and Larsson 2003). Non-breeding Outside of the breeding season the species remains along the shores of coastal habitats (e.g. rocky offshore islands), coastal dykes, coastal dunes and estuaries but also frequents settlements, cattle pens and fishing harbours (in Africa) (Urban et al. 1986, del Hoyo et al.1996, Olsen and Larsson 2003). Diet Its diet consists predominantly of fish, as well as invertebrates (e.g. insects, molluscs and termites), the eggs of herons and cormorants, and dead fish and refuse obtained by scavenging (Urban et al. 1986, del Hoyo et al. 1996).Breeding site The species breeds colonially, with nests often placed less than 1m apart (del Hoyo et al. 1996). Nests are positioned on bare ground, in clumps of reeds and papyrus, on islands, or on floating vegetation, often camouflaged in tall, thick vegetation (Urban et al.1986, del Hoyo et al. 1996). The nest itself varies from a shallow scrape to a well built cup of rushes and grasses depending on location, although floating nests are always substantial (Urban et al. 1986, del Hoyo et al. 1996).
Egg collecting in colonies in west Africa is considered a serious problem, and likely drives local declines in the population (Burger et al. 2018).
Text account compilers
Malpas, L., Calvert, R., Martin, R., Ekstrom, J., Butchart, S.
BirdLife International (2020) Species factsheet: Larus cirrocephalus. Downloaded from http://www.birdlife.org on 27/01/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 27/01/2020.