|Scientific Name:||Pagophila eburnea (Phipps, 1774)|
|Taxonomic Source(s):||Cramp, S. and Simmons, K.E.L. (eds). 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Reviewer(s):||Butchart, S. & Symes, A.|
|Contributor(s):||Gavrilo, M., Miljeteig, C., Stenhouse, I., Strom, H., Volkov, A. & Anderson, O.|
|Facilitator/Compiler(s):||Ashpole, J, Butchart, S., Calvert, R., Derhé, M., Ekstrom, J., Fisher, S., Harding, M., Malpas, L., Moreno, R., Wheatley, H.|
This species has declined rapidly in parts of its range, but its status in other areas is poorly known. A number of factors are likely to be contributing to declines, including climate change, pollution and increasing human intrusion or hunting within breeding areas. It is currently considered Near Threatened; but further surveys are required in order to clarify the true magnitude of declines.
|Previously published Red List assessments:|
This species has a circumpolar distribution in the Arctic seas and pack-ice during nonbreeding season, while its breeding range is confined to the Arctic Atlantic sector. It breeds from Canadian Arctic Archipelago (to Canada) through Greenland (to Denmark), Svalbard (Svalbard and Jan Mayen Islands (to Norway), and islands of Franz-Josef Land, Severnaya Zemlya and offshore islands in the Kara Sea (to Russia). In Russia, there are 55 known sites where Ivory gulls have bred or have been breeding until now (Gavrilo 2009). During the past 25 years, 38 breeding sites have been confirmed, 8 historical sites have been abandoned and 10 remain unsurveyed. Using all data obtained recently and the current knowledge on Ivory’s gull biology, populations have been estimated at 1,000-1,500 breeding pairs on Franz-Josef Land (European Russia), 1,500-3,000 pairs on Severnaya Zemlya and 1,000-2,500 pairs in the rest of the Kara Sea Islands (Central Asian Russia) (M. Gavrilo, unpubl. data). During the last 5 years, the numbers of breeding pairs varies highly between seasons and also inter-annually. For example, the colony on Sedov Archipelago (Severnaya Zemlya) had 2,000 breeding pairs in 2006-2007, but has held between 100 and 1,000 pairs in other years. Also, the total numbers for 5 of the monitored colonies dropped from a maximum of 2,720 breeding pairs observed during 1990s-2000s to 450 pairs in 2016. Overall, no large-scale survey covering most of the key colonies during the same single season has been performed after 2006 and, thus, further research is need to assess the overall Russian population estimate and trend.Other populations include 1,000 individuals in northeast Canada (Hess 2004, Gilchrist and Mallory 2005, Mallory pers.comm. 2016), 900-2,000 pairs (equating to 2,700-6,000 individuals) in Greenland (BirdLife International 2015), and 800-1,500 pairs (equating to 2,400-4,500 individuals) in Svalbard (BirdLife International 2015). Extrapolations based on aerial estimates suggested >35,000 individuals between Canada and Greenland in 1978-1979 (Orr and Parsons 1982). The global population is perhaps best placed in the band 58,000-78,000 individuals.
Recent surveys have revealed a drastic decline in Canadian populations, falling from 2,400 birds in 1987 to 500-700 birds in 2002-2003 (Hess 2004), representing an 80% decline in that period across the Canadian breeding range in all three known nesting habitat types (Gilchrist and Mallory 2005). The species seems to be declining in the south of its Greenland breeding range, while in North Greenland the trends are unclear (Gilg et al. 2009). However, the overall population trend in Greenland is estimated to be decreasing (BirdLife International 2015).
Native:Canada; Greenland; Russian Federation (Central Asian Russia - Vagrant, Eastern Asian Russia, European Russia); Svalbard and Jan Mayen; United States
Vagrant:Belgium; Czech Republic; Denmark; Faroe Islands; Finland; France; Germany; Iceland; Ireland; Italy; Japan; Netherlands; Norway; Poland; Saint Pierre and Miquelon; Sweden; Switzerland; United Kingdom
|Range Map:||Click here to open the map viewer and explore range.|
Using all data obtained recently and the current knowledge on Ivory’s gull biology in Russia, populations have been estimated at 1,000-1,500 breeding pairs on Franz-Josef Land (European Russia), 1,500-3,000 pairs on Severnaya Zemlya; and 1,000-2,500 pairs in the rest of the Kara Sea Islands (Central Asian Russia) (M. Gavrilo, unpubl. data). An estimated 1,000 pairs were recorded in northeast Canada (Hess 2004, Gilchrist and Mallory 2005, Mallory pers.comm. 2016), 900-2,000 pairs in Greenland between 2000 and 2012 and 800-1,500 pairs in Svalbard between 2001 and 2013 (BirdLife International 2015). Orr and Parsons (1982) recorded aerial estimates of possibly more than 35,000 individuals between Canada and Greenland in 1978-1979, while del Hoyo et al. (1996) estimated possibly 25,000 pairs (75,000 individuals). This gives a total of 58,100-77,200 individuals, rounded here to 58,000-78,000 individuals, roughly equivalent to 38,000-52,000 mature individuals.
Trend Justification: Trends are difficult to estimate as colony size fluctuates from year to year, but sustained declines have been recorded in Canada. The European population is estimated to be fluctuating (BirdLife International 2015). Further information is required on long-term trends in other areas.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
Behaviour This species is migratory (Olsen and Larsson 2003). It breeds between late June and August (although most pairs do not lay until early-July). Most of the colonies in Canada, Greenland and Svalbard hold between 1-100 pairs (del Hoyo et al. 1996, Gavrilo et al. 2007, Volkov de Korte, 2000). Breeding numbers in the same colony in a given season is a subject of great (up to 10 fold) inter-annual fluctuations depending on ice conditions (food availability) during pre-breeding season (Gavrilo 2011a, Eamer et al. 2013). There is also inter annual alteration between different breeding sites (Bangjord et al. 1994, Mallory 2005, Robertson et al. 2007, McDonald, 1976, Volokov and De Korte, 1996, 2000, Gavrilo 2011a, Spencer et al. 2012). It departs from the breeding grounds during August - first half of October, returning late-February to early-June (Malory et al. 2008, Olsen and Larsson 2003, Volkov and De Korte 2000, Gilg et al. 2010, Spencer et al. 2014). Most active migration occurs in November, with the first birds only arriving on the wintering grounds in December (Bering Sea, southeast Greenland, Davis Strait/Labrador Sea), and with birds from Greenland, Svalbard, and Russia arriving in sequence (Gilg et al. 2010). Most of the birds wintering in the Pacific are thought to originate from the largest Russian colonies, Kara Sea Islands and Severnaya Zemlya (Gilg et al. 2010). Between July-December, they may travel 50,000 km on average, and even more for individuals that move to the Pacific (Gilg et al. 2010). Outside of the breeding season the species is weakly gregarious, occurring singly or in flocks of up to 20 individuals (Snow and Perrins 1998) or up to 2,000 individuals in favourable feeding places (Renaud and McLaren 1982, Lydersen et al. 2014). Larger numbers also gather in the spring at hooded seal Crystophora cristata whelping sites, where they feed on carrion and discarded placentae (del Hoyo et al. 1996). The species also regularly follows polar bears Thalarctos maritimus to feed on scraps from their kill (del Hoyo et al. 1996). Habitat Breeding It breeds on the high Arctic islands north of the July 5oC isotherm (Snow and Perrins 1998). Twelve different habitats are described for the species (Gavrilo 2011b) which are grouped into two principal categories: i) relatively inaccessible coastal or inland (up to 50 km from the coast, Wright and Matthews 1980; Gilg et al. 2009) rocky mountains and cliffs up to 750 m high (Frisch and Morgan, 1979) and ii) a variety of flat-ground habitats including plain polar deserts, gravel and sandy spits, stony plateau, small gravel/bare islands (del Hoyo et al. 1996, Snow and Perrins 1998, Gavrilo, 2011b), or even icebergs (MacDonald, Macpherson, 1962, Boertmann et al. 2010, Nachtsheim et al. 2015) or grounded ice floes (Kristoffersen, 1931) as well as abandoned wooden buildings and other human artefacts (Gavrilo 2011b). In general, spatial-territorial patterns of ivory gulls breeding colonies distribution are affected by the terrestrial predation, mostly by Arctic foxes (Gavrilo 2011b, 2012). Non-breeding Outside of the breeding season it strongly associates with sea ice (del Hoyo et al. 1996, Gilg et al. 2010, Spencer et al. 2014) with preference to the marginal pack-ice zone. Wintering in Davis Strait, ivory gulls were found to use persistently ice areas with predictable and valuable food resources provided by remains of breeding and polar bear kills at the whelping patches of hooded seals Crystophora cristata (Spencer et al. 2016). The timing of formation and recession and extent of sea ice is suggested to play a large role in their distribution and migratory timing (Spencer et al. 2012). Diet Its diet consists predominantly of fish, crustaceans, molluscs, and carrion (e.g. seal placentae) (del Hoyo et al. 1996, Mallory et al. 2008, Karnovsky et al. 2009). The species is supposed to occupy upper trophic levels during the entire annual cycle, making ivory gull vulnerable for accumulation of toxic substances (Spencer et al. 2014). It feeds mostly by hovering and contact dipping in open leads in ice-filled waters or at the glacier fronts, walking along ice-floe edges and along the sandy beaches, or scavenging on marine mammal remains (Divoky 1981, Renaud and McLaren 1982, Mallory et al. 2008, Karnovsky et al. 2009, Lydersen et al. 2014, Gavrilo, pers. comm.). Breeding site The nest is constructed of mosses and available vascular plants, straw and other debris on a snow-free area of broad rock ledges on steep, inaccessible coastal or inland cliffs up to 300 m high; on gravel, sand or clay ground; broken ice-fields and bare, level shorelines with low rocks; or on ledges, logs or roofs of abandoned buildings (del Hoyo et al. 1996, Snow and Perrins 1998, Gavrilo 2011a,b, Mallory et al. 2008, Volkov and de Korte 2000). The species avoids areas with developed tundra vegetation (Gavrilo 2011b).
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Generation Length (years):||28|
|Movement patterns:||Full Migrant|
|Congregatory:||Congregatory (and dispersive)|
The species is thought to be declining due to changes in conditions on its staging or wintering grounds (e.g. more severe winters, changing sea-ice distribution and thickness) (Gilchrist and Mallory 2005, Gilg et al. 2010, Spencer et al. 2012, Joiris 2016). The species is hunted (Gilchrist and Mallory 2005). Potential causes of the decline identified in Canada include illegal hunting (Stenhouse et al. 2004), oiling at sea, disturbance of colonies due to escalating diamond exploration and/or increased nest predation, and toxic pollutants that bioaccumulate at high trophic levels (Braune et al. 2006). The species' reliance on seal and whale blubber makes it particularly vulnerable to heavy metal contamination (Tucker and Heath 1994, Spencer et al. 2014). The levels of organochlorinated pesticides (OCPs), polychlorinated biphenyls (PCBs) and mercury (Hg) in ivory gulls are among the highest ever reported in Arctic seabirds (Braune et al. 2006; Miljeteig et al. 2009, Lucia et al. 2015). Canadian birds are mostly contaminated with mercury, and concentrations of total mercury in their eggs have steadily increased since 1976 to levels which are now among the highest measured in seabirds (Braune et al. 2006). Other populations have highest levels of PCB and DDT in their eggs (Miljeteig et al. 2009, Lucia et al. 2015), which may have had a long-term effect on breeding productivity (Miljeteig 2012). In addition, the levels of other contaminants (e.g. organochlorines, brominated flame retardants, perfluorinated alkyl substances were found at highest levels in Greenland birds (Lucia et al. 2015). Overall, the levels of OCs, BFRs, and PFASs did not suggest direct lethal exposure to these compounds, but their potential synergetic/additive sublethal effects warrant monitoring (Lucia et al. 2015).
In recent years following rapid industrial exploration of the Arctic shelf, remote ivory gull breeding sites became at risk of area claim and human intrusion. This threat is especially relevant for the coastal flat-ground breeding colonies in the Russian Kara Sea, where oil and gas industries develops rapidly. Growing shipping along the Northern Sea Route, including transport of oil, as well as oil exploration and exploitation at sea pose potential hazard of oil spills and chronic oil discharge to the sea. In Franz Josef Land, one breeding site (hold recently up to 300 breeding pairs in a few colonies) was recently lost due to military development of the area. Growing tourist activity in the Arctic is also a potential threat to the flat-ground colonies since ivory gulls are very sensitive to disturbance during breeding season.
Conservation Actions Underway
Bern Convention Annex II. In Russia, it was listed in the Red Data Book of the U.S.S.R. (1984) and is currently registered as a Category 3 (Rare) species in the Red Data Book of the Russian Federation. As a result, the species is listed in regional Red Data Books along its breeding range in Russia (Gilchrist et al. 2008). However there are currently no specific conservation measures in action for this species (Varty and Tanner 2009). A Norwegian-Russian project satellite tagged 31 individuals in 2007/2008 to assess movements at breeding grounds and their dispersal ability (Gilg et al. 2009). Conservation Actions Proposed
Monitor population trends throughout the range, with particular emphasis on determining rates of decline in main breeding areas. Research the magnitude of threats facing all populations. Protect colonies from mining actions and other intrusion (military activities, oil industry infrastructure) and disturbances (tourism).
|Amended reason:||Map edited: Minor adjustment to edge of map. EOO updated.|
|Citation:||BirdLife International. 2017. Pagophila eburnea (amended version of 2017 assessment). The IUCN Red List of Threatened Species 2017: e.T22694473A118603183.Downloaded on 19 September 2018.|
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