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.
PERSGA/GEF (2003) estimated there to be 12,000-13,000 pairs (excluding Eritrea), while Semere et al. (2008) recorded 5,900 pairs on Eritrean Islands. Thus the overall population size may be 35,800-37,800 mature individuals, which equates to 53,700-56,700 individuals in total.
The population is believed to be stable (Rose and Scott 1997, Symes et al. 2015).
Larus leucophthalmus breeds colonially on inshore islands and islets in the Gulf of Aden and the Red Sea, in Egypt (mainly on islands at the mouth of the Gulf of Suez), Sudan, Eritrea (Dahlak Archipelago), Djibouti, Saudi Arabia, Yemen and Somalia. Wintering birds disperse throughout the breeding range.
Behaviour The species is mostly sedentary (Urban et al. 1986, del Hoyo et al. 1996), although it disperses from its breeding sites to occur throughout the Red Sea during the non-breeding season (Olsen and Larsson 2004). There may also be some southward and eastward movements during this time, when it is reported to become scarce in the northern part of its range (Urban et al. 1986). Breeding takes place during the months of June - August, extending to September in Egypt (Urban et al. 1986). It breeds in loose colonies, usually consisting of fewer than 25 pairs, though occasionally larger colonies of hundreds of individuals can be observed (del Hoyo et al. 1996). During the non-breeding season, it is usually found in small groups, but sometimes forms flocks of hundreds or even thousands to forage (del Hoyo et al. 1996).
Habitat The species is mainly coastal. It usually feeds at sea (PERSGA/GEF 2003), but some Egyptian populations have adopted a scavenging role at rubbish tips, harbours and touristic area along the Egyptian Red Sea Cost (S. Baha El Din verbally to A. Grieve 1999, M. Mohamed in litt. 2016). Breeding It breeds on inshore islands, where it occupies bare rock and sand flats (del Hoyo et al. 1996). Non-breeding Outside the breeding season, it often occurs further out to the sea (del Hoyo et al. 1996). It roosts on rocks, coral reefs, piers and fishing vessels (del Hoyo et al. 1996).
Diet The diet consists largely of fish, but also includes crustaceans, molluscs, annelids and offal (del Hoyo et al. 1996, PERSGA/GEF 2003). Fish species taken in Egypt include Scarpus spp. about 110 mm in length (Urban et al. 1986). It also feeds on fruits and plants such as Nitraria retusa (Urban et al. 1986) and is known to predate the eggs and nestlings of the Lesser Crested Tern Sterna bengalensis (Urban et al. 1986). It scavenges in the northern part of its range, feeding on all types of food (i.e. meat, rice, bread, water melon and flying insect [Habib 2017]), but to a lesser extent than does L. hemprichii with which it often associates (Urban et al. 1986, del Hoyo et al. 1996).
Breeding Site Nests occur on bare rock, sand or exposed flats (del Hoyo et al. 1996). On sandy substrates the nest consists of a conspicuous ring of twigs, seaweed and debris (Urban et al. 1986). On rocky islands it consists of a small pad of vegetable matter beside rocks (Urban et al. 1986). It may alternatively consist of a scrape among impenetrable Euphorbia clumps (Urban et al. 1986). It lays two or three eggs (del Hoyo et al. 1996).
Introduced invasive species pose a significant threat on breeding islands (Del Hoyo et al. 1996), and rat tracks have been found in and around colonies in Djibouti (Shobrak 2007). Due to its ground nesting habit, it is particularly vulnerable to loss of reproductive success through nest predation (Urban et al. 1986). Cats have been introduced on several islands by army personnel and have been found near colonies and may be having an effect on the species (Shobrak 2007). The impact on nesting birds could be very large, causing disturbance and a loss of reproductive success but has not been assessed (Ibrahim 2009).
Breeding birds are also disturbed by tourists (including safaris, land and overnight stays on islands) (Habib 2017) and the use of dune buggies on many islands is known to be a serious issue for breeding birds in colonies in Egypt (Ibrahim 2009). Further to this, coastal development throughout the species' range has destroyed large tracts of suitable environment, birds are now absent from islands with significant development associated with the tourist industry (Shobrak 2007). Egg and chick collection is traditionally carried out by fishers with knowledge of bird colony locations in the Red Sea (Almalki et al. 2014), this is not thought to be widespread in all areas but could be having considerable impact locally (Ibrahim 2009). Fishers are also known to cause disturbance to breeding colonies (del Hoyo et al. 1996).
The White-eyed Gull is also threatened by oil pollution from both floating and beached oil spills (del Hoyo et al. 1996, Habib 2017) with pollution of surface water threatening breeding birds during nesting season. Oil pollution is thought to threaten this species across its range in Egypt (Ibrahim 2009). The use of dynamite in submarine oil exploration along the coast threatens bird colonies, causing disturbance, habitat loss and habitat degradation, this was common practice in the past and is thought to still be practiced in some parts of the Red Sea (Ibrahim 2009).
Conservation Actions Underway
CMS Appendix I and II.
41 cm. A rather dark gull with black head in adult plumage. Adult has grey back, complete black hood with an almost continuous white eye ring and rather long, dark red bill. Juvenile is brown above with a brownish wash on head, breast and flanks; the bill is black and there is a black tail band. All ages have a dark underwing. Similar spp. Told from Sooty Gull Larus hemprichii by slightly smaller size, and, in adult plumage, all-black hood and bib, dark grey upperparts, all-dark bill (dark red with black tip, unlike two-tone bill of Sooty Gull) and conspicuous white eye-ring. Hints Often associates with Sooty and other gulls around fishing ports on the Red Sea.
Text account compilers
Shutes, S., Starkey, M., Stuart, A., Taylor, J., Westrip, J., Hermes, C., Butchart, S., Martin, R., Moreno, R., O'Brien, A., Evans, M., Palmer-Newton, A., Pilgrim, J.
Habib, M., Grieve, A., Baha El Din, S.
BirdLife International (2020) Species factsheet: Larus leucophthalmus. Downloaded from http://www.birdlife.org on 05/07/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 05/07/2020.