This discussion was first published as part of the 2015 Red List update. At the time a decision regarding its status was pended, but to enable potential reassessment of this species as part of the 2017 Red List update this post remains open and the date of posting has been updated.
Black-legged Kittiwake (Rissa tridactyla) breeds in the North Atlantic, from NC Canada and NE USA east through Greenland to W & N Europe, and on to the Taymyr Peninsula and Severnaya Zemlya, wintering south to the Sargasso Sea and W Africa; and in the North Pacific, from NE Siberia, Kamchatka, Sea of Okhotsk and Kuril Is through Bering Sea to Alaska, wintering south to East China Sea and NW Mexico (Burger et al. 2014). It is currently listed as Least Concern, because when last assessed it was not thought to approach the thresholds for Vulnerable under any of the IUCN Red List criteria.
Globally, it has an extremely large range in both the breeding season (>1.6 million km2) and in winter (>50 million km2), and hence does not approach the thresholds for Vulnerable under the range size criteria (B and D2). Its population size is also extremely large (14–16 million individuals; Coulson 2011, Wetlands International 2012), and hence does not approach the thresholds for Vulnerable under the population size criteria (C and D1). Therefore, the only potentially relevant criterion is A, which relates to reductions in population size. Until recently, the population was thought to be declining slowly, but not sufficiently rapidly to approach the threshold for listing as Vulnerable under criterion A (at least a 30% decline over ten years or three generations, whichever is longer).
New data collated from across Europe for the European Red List of Birds (BirdLife International 2015) indicate that the species has declined significantly in recent years, and that this decline is ongoing. A combination of official data reported by 27 EU Member States to the European Commission under Article 12 of the EU Birds Directive and comparable data from other European countries, provided by BirdLife Partners and other leading national ornithologists, suggests that the European population has declined markedly since the 1980s, and is currently estimated and projected to be declining overall at a rate of >40% over three generations (39 years, based on a generation length estimated by BirdLife to be 13 years). This corresponds well with the significant long-term decline reported by Berglund & Hentati-Sundberg (2014). Consequently, the species is now classified as Vulnerable at European level (BirdLife International 2015).
Based on the latest population estimates (Coulson 2011, Wetlands International 2012), Europe (including Greenland) holds >50% of the global population, so the declines in Europe are globally significant. The small Canadian Arctic population is increasing by 1% per year (Mallory et al. 2009, Gaston et al. 2012), but as in Europe, the species’ breeding productivity in Alaska has declined since the 1980s, and numbers have decreased sharply in some colonies, possibly as a result of a regime shift in the North Pacific (Hatch 2013). However, no recent information is available about the overall trend of the North Pacific population.
Given the size of the European population, the magnitude and scale of recent ongoing declines in Europe, and the absence of any evidence of compensatory increases elsewhere in its range, this species appears likely to qualify for uplisting from Least Concern under criterion A. To complete the global picture and inform which category is most appropriate, data are sought on recent overall trends in the North Pacific, along with any additional information about the threats currently affecting this species across its range.
Berglund, P. A. & Hentati-Sundberg, J. (2014). Arctic Seabirds Breeding in the African-Eurasian Waterbird Agreement (AEWA) Area: Status and Trends 2014. AEWA Conservation Status Report (CSR6) background report. http://www.wetlands.org/Portals/0/PAB%20AEWA%20report%20review%202014.pdf
BirdLife International (2015) European Red List of Birds. Luxembourg: Office for Official Publications of the European Communities. http://www.birdlife.org/datazone/info/euroredlist
Burger, J., Gochfeld, M., Kirwan, G.M. & Christie, D.A. (2013). Black-legged Kittiwake (Rissa tridactyla). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2013). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. www.hbw.com
Coulson, J. (2011). The Kittiwake. Bloomsbury Publishing.
Gaston, A. J., Mallory, M. L., & Gilchrist, H. G. (2012). Populations and trends of Canadian Arctic seabirds. Polar biology, 35(8), 1221-1232.
Hatch, S. A. (2013). Kittiwake diets and chick production signal a 2008 regime shift in the Northeast Pacific. Mar Ecol Prog Ser, 477, 271-284.
Mallory, M. L., Akearok, J. A., Gaston, A. J. (2009) Status of High Arctic Black-Legged Kittiwake (Rissa tridactyla) Colonies in Barrow Strait, Nunavut, Canada. Arctic 62: 96-101.
Wetlands International (2012) Waterbird Population Estimates: 5th edition. wpe.wetlands.org