Justification of Red List Category
This species is listed as Vulnerable because it is suspected that it will undergo rapid population declines in the next three generations. It breeds at a small number of wetland locations in arid regions which are vulnerable to human disturbance and strongly influenced by changes in climate, and it now appears that the vast majority of birds are dependent on intertidal habitats in the Bohai Bay during the non-breeding season. The severe and increasing threat of reclamation of these coastal wetlands for development is likely to be the primary driver of future declines.
The population was estimated at 12,000 individuals by Rose and Scott (1997); however, over 7,000 nests were recorded in 2010 and 2011 in the Ordos uplands of western Inner Mongolia and northern China (He Fenqi in litt. 2011), strongly suggesting that the total number of mature individuals exceeds the previous estimate. The population is thus placed in the band for 10,000-19,999 mature individuals, equating to 15,000-29,999 individuals in total, rounded here to 15,000-30,000 individuals.
Populations at some breeding sites, e.g. Honjian Lake, have increased, whilst others have declined dramatically, and population trends are difficult to interpret. However, the population is suspected to be decreasing at a moderate rate, as threats such as the reclamation of coastal wetlands for development, and human disturbance at breeding sites, and instability of breeding areas owing to weather fluctuations continue to influence most of the range. Loss of ephemeral wetland habitats in arid regions, associated with climate change, could greatly affect this species in the near future, and the rate of reclamation of coastal wetlands for development is also predicted to increase. It is therefore suspected that the population will undergo rapid declines of 30-49% over the next three generations.
Larus relictus breeds at two localities in eastern Kazakhstan (but regularly at only one [Rubini and Berezovikov 2002]), one in Russia and several in Mongolia, whilst the largest colonies are thought to occur in China, at Honjian Nur Lake, Shaanxi (up to 5,000 pairs [He Fenqi and Ren Yong-qui 2006]) and previously at Taolimiao-Alashan Nur on the Ordos Plateau in Inner Mongolia (up to 3,000 pairs [He Fenqi and Qiao Zhenzhong in litt. 2004]), although this site was recently abandoned (He Fenqi and Ren Yong-qui 2006).
Its non-breeding range is poorly understood, but some are known to winter in South Korea, whist large numbers (7,880 near Tanggu, coastal Tianjin [P. Holt in litt. 2012], 10,405 at Hangu, Tianjin in March 2010, Townshend 2015) have been found at Bohai Bay on the coast of eastern China, and over 8,000 have been counted in the Nanpu-Caofedian area of coastal Tangshan, Hebei (per P. Holt in litt. 2011). It was previously thought that some birds wintered inland on the northern flank of the Qinghai-Tibet plateau, China, but this assertion appears to have derived from a record of a single individual in 1989/1990. It is now considered far more likely that the species is entirely restricted to intertidal coastal areas in the non-breeding season (N. Moores in litt. 2017). It is likely that at least 90% of the population winters along the shores of the Yellow Sea, concentrated at a very few sites in Tianjin and Hebei Provinces, Bohai Bay, China, with the remainder suspected to winter along the east coast of the Korean Peninsula, in the southern part of the Yellow Sea, and along the East China Sea coast (N. Moores in litt. 2017).
Both breeding and wintering ranges are known to fluctuate widely in response to weather conditions. The population has been estimated at 12,000 individuals (Rose and Scott 1997); however, counts of over 7,000 nests in the Ordos uplands of Inner Mongolia and in northern China in 2010 and 2011 (per He Fenqi in litt. 2011) suggest that the number of mature individuals exceeds the previous estimate and probably falls somewhere in the region of 10,000-19,999.
All known breeding colonies are below 1,500 m, in the arid-steppe zone, on islands in saline and slightly saline lakes with fluctuating water-levels. No nesting occurs if lakes dry up, if the islands become joined to the shore, or if the water-level is too high and the islands become too small or overgrown with vegetation.
In the non-breeding season foraging Relict Gulls are near-confined to tidal flats with firmer sandy substrates and patches of silt or mud (typically the outer parts of estuaries) which support a high concentration of shellfish, with only a few individuals (mostly first-winters) also found on sandy beaches in bays and close to river mouths (N. Moores in litt. 2017).
Changes in water-level affect breeding success, and the loss of ephemeral wetland habitats in arid regions, associated with climate change, could greatly affect this species in the near future (He Fenqi et al. 2005), although geographic shifts and fluctuations could result, rather than chronic declines. Climate models used to predict scenarios until 2080 suggest a trend of increasing aridisation of current steppe areas in Kazakhstan and an overall shift of vegetation zones into Siberia (Tchebakova et al. 2009), probably resulting in the drying-out of shallow saline lakes used for nesting in north-eastern Kazakhstan, although many lakes in southern Siberia would be expected to become more saline owing to these climatic changes, providing replacement habitat for this mobile species (J. Kamp in litt. 2012). The former breeding site of Lake Balkhash is unlikely to be recolonised if the drying trend there continues (J. Kamp in litt. 2012). The major breeding colony at Taolimiao-Alashan Nur, China, has been affected by recent tourist developments, and habitat degradation since 2002, caused by drought, human disturbance and unsustainable water use, has resulted in the absence of nesting activity by this species since 2006 (He Fenqi in litt. 2011). For similar reasons Hongjian Nur in the Ordos uplands has decreased from an area of over 60 km2 to c.40 km2, with an increased pH value of up to 9.6, thus threatening the colony there (He Fenqi in litt. 2011), with a further decrease to c.32.8 km2 and a pH value of 9.8 recorded in 2016 (Anon 2016). Competition for breeding sites and predation by other gulls, as well as mortality from hailstorms and flooding, can affect breeding productivity. Human disturbance has caused increased mortality of eggs and chicks in Russia and China, by making them vulnerable to bad weather, predation and desertion.
In South Korea, most of the mudflats at the Nakdong estuary have been reclaimed and it is likely that many other coastal wetlands are under similar pressure from development. The major wintering area at Bohai Bay, China, has been affected by reclamation for oilfields, harbours, roads and other developments, and plans are in hand to reclaim 43% of the remaining habitat (Yang Liu et al. 2006). In addition, the Bohai Sea is amongst the world's most polluted, and expansion of offshore oil extraction in Bohai Bay will increase the likelihood of spills, such as those that occurred from the Penglai offshore oilfield in June 2011 (P. Holt in litt. 2011). Other coastal wintering areas are under threat from development, as demonstrated by a massive reclamation project in Tianjin, resulting in the displacement of the wintering population northwards to the Nanpu-Caofedian area of coastal Tangshan, Hebei, which is in turn threatened by another reclamation project (P. Holt in litt. 2011). Another threat in coastal wintering areas of that of disturbance caused by increasingly mechanised shellfish harvesting (P. Holt in litt. 2011). The site in Tianjin where a single flock of 10,405 (the majority of the world population) were counted in March 2015 is said to be threatened with imminent reclamation (Townshend 2015).
Conservation and research actions underway
CITES Appendix I. CMS Appendix I. It is protected from hunting in Russia. A nature reserve was established to protect breeding sites in Alakol' Lake (Kazakhstan). Breeding sites in Russia are protected in the Tsasuchey-Torey Sanctuary and several localities in Mongolia are Ramsar Sites. A poster campaign has been carried out to inform communities on the Ordos Plateau about the importance of the breeding colonies. A nature reserve has been delimited around the major breeding site at Taolimiao-Alashan Nur, China (He Fen-qi and Qiao Zhen-zhong in litt. 2004). The China Biodiversity Conservation and Green Development Foundation have set up a Community Conservation Area for the species at Tianjin (S. Huang in litt. 2017).
44-45 cm. Medium-sized, thickset gull. Similar spp. Non-breeding adults are larger, stockier, thicker-billed and longer-legged than Brown-headed Gull L. brunnicephalus and Black-headed Gull L. ridibundus, with more uniformly dark-smudged ear-coverts and hind crown, white-tipped primaries, prominent, isolated black subterminal markings on outer primaries, and no white leading edge to outer wing. Breeders are black-hooded (including nape), with broad, broken white eye-ring.
Text account compilers
Symes, A., Harding, M., Westrip, J., Gilroy, J., Benstead, P., Taylor, J.
Townshend, T., Qiao, Z.-Z., Moores, N., Kamp, J., Holt, P., Huang, S., He, F.
BirdLife International (2018) Species factsheet: Larus relictus. Downloaded from http://www.birdlife.org on 16/07/2018. Recommended citation for factsheets for more than one species: BirdLife International (2018) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 16/07/2018.