Last updated 4 May 2023

The kittiwake (Rissa tridactyla) obtains its food from the sea surface and hence functions as an indicator for this part of the marine ecosystem. This pelagic gull comprises a large proportion of the sea birds, in terms of both biomass and food consumption, and is dispersed over the whole of Svalbard and the rest of the Arctic.

Kittiwakes breeding at Bjørnøya, Svalbard. Photo: Malin Kjellstadli Johansen / Norwegian Polar Institute

What is being monitored?

Population size on Bjørnøya and Spitsbergen

For each colony, the population size is shown as a percentage of the average in the colony during the entire monitoring period. The time series represents active nests in delimited parts of the colony, so-called plots. The time series for the different colonies can be on different scales, therefore, by using percentage of the average the time series can be shown on a common scale. The kittiwake population in Svalbard and on Bjørnøya declined in the years prior to 2002–2003. It has since recovered in most of the colonies and have been stable or increasing since. The population in Svalbard has remained relatively stable over the entire monitoring period taken as a whole.
(Cite these data: Norwegian Polar Institute (2023). Black-legged kittiwake population size, as percentage of the average in the colony. Environmental monitoring of Svalbard and Jan Mayen (MOSJ). URL:

Details on these data

Last updated4 May 2023
Update intervalYearly
Next updateApril 2024
Commissioning organizationMinistry of Climate and Environment
Executive organizationNorwegian Polar Institute
Contact personsSébastien Descamps
Hallvard Strøm


Monitoring of five colonies on Spitsbergen Ossian Sarsfjellet (Kongsfjorden), Fuglehuken (Forlandet) and Alkhornet, Tschermakfjellet and Grumant (Isfjorden), one colony on the east side of Spitsbergen (Alkefjellet, Hinlopen) and Bjørnøya. Some monitoring was previously conducted in the colonies in Sofiekammen and on Amsterdamøya on the west coast of Spitsbergen, but this work has not been continued since 2001.

Three counts of each plot (one count per observer) are made 1-4 times per season, from late incubating to early rearing period. Counts are made with 10×40 binoculars.


The method is internationally standardized (Walsh et al. 1995) and is also standardized with the SEAPOP Norwegian monitoring.

Other metadata

All data are stored in the Norwegian Polar Institute’s seabird database, as well as in SEAPOP’s databases.

Reference level and action level

The 15-30 % reduction in the Svalbard population in the late 1990s and the beginning of the 2000s makes the species qualified for the category “Near Threatened” in the Norwegian Red List.

Barents Sea Management Plan (monitoring group): a reduction in the population of 20 % or more for more than 5 years, or unsuccessful breeding 5 years in a row.

Status and trend

The Svalbard population of black-legged kittiwakes has probably increased during the last century, but most colonies in the Atlantic and Pacific oceans are declining. In Svalbard most of the monitored  colonies  on Bjørnøya and Spitsbergen  remain stable or are even increasing slightly, after a period of decline during the 1990s. Since around 2002, most of the monitored colonies on Bjørnøya and Spitsbergen have been stable or have increased slightly. The reason for the trend in some of the colonies in Svalbard is unknown. Since the colonies east of Svalbard have only been monitored since 2015, the overall trend for the Svalbard population is unclear.

In mainland Norway the species is declining rapidly, and black-legged kittiwakes are since 2021 classified as Endangered (mainland) and Near threatened (Svalbard) on the Norwegian Red List.

Causal factors

The reason for the decline in some Svalbard colonies of kittiwakes is not known.


Considering that the overall status and trend of black-legged kittiwakes in Svalbard is unclear, the consequences for other parts of the ecosystems in Svalbard are also unclear.

About the monitoring

The black-legged kittiwake is the most numerous species of gull in the world and the most oceanic in its habits.

In Svalbard, the black-legged kittiwake is a common breeding species in all parts of the archipelago. The black-legged kittiwake is a surface-feeding bird (in contrast to other sea birds) that mainly feeds on invertebrates and small fish, but it also scavenges offal or discarded fish behind fishing boats. Chicks are fed regurgitated food. In Svalbard, capelin, polar cod, amphipods and euphausiids are common components of their diet. The total breeding population is estimated to be 270,000 pairs, of which ca 90,000 pairs breed on Bjørnøya.

Black-legged kittiwakes are monitored on Bjørnøya and in western Spitsbergen. The size of several colonies is estimated annually in order to detect short- and long-term changes in population size. Moreover, to explain and even predict those changes, several other parameters are monitored such as the annual adult survival and the average breeding success.

In addition, studies using GLS (light loggers) are used to study activity patterns, migration routes and winter ecology.

Relations to other monitoring

Monitoring programme

International environmental agreements

  • None

Voluntary international cooperation

Related monitoring

Further reading



  1. Anker-Nilssen, T., Strøm, H. 2010. Nytt klima for sjøfugl? Sjøfugl – Speiler havets tilstand – Ottar 5/2010. Ottar 283: 73–81.
  2. Descamps, S., Anker-Nilssen, T., Barrett, R.T., Irons, D.B., Merkel, F., Robertson, G.J., Yoccoz, N.G., Mallory, M.L., Montevecchi, W.A., Boertmann, D., Artukhin, Y., Christensen-Dalsgaard, S., Erikstad, K.-E., Gilchrist, H.G., Labansen, A.L., Lorentsen, S.-H., Mosbech, A., Olsen, B., Petersen, A., Rail, J.-F., Renner, H.M., Strøm, H., Systad, G.H., Wilhelm, S.I., Zelenskaya, L. 2017. Circumpolar dynamics of a marine top-predator track ocean warming rates. Global Change Biology 23: 3770-3780.
  3. Descamps, S., Ramírez, F., Cunningham, S. (ed.) 2021. Species and spatial variation in the effects of sea ice on Arctic seabird populations. Diversity and Distributions.
  4. Descamps, S., Strøm, H. 2021. As the Arctic becomes boreal: ongoing shifts in a high‐Arctic seabird community. Ecology.
  5. Frederiksen, M., Edwards, M., Mavor, R.A., Wanless, S. 2007. Regional and annual variation in black-legged
    kittiwake breeding productivity is related to
    sea surface temperature
    . Marine Ecology Progress Series 350: 137–143.
  6. Frederiksen, M., Wanless, S., Harris, M.P., Rothery, P., Wilson, L.J. 2004. The role of industrial fisheries and oceanographic change in the decline of North Sea black-legged kittiwakes. Journal of Applied Ecology 41(6): 1129–1139.
  7. Lorentsen, S.-H., Strøm, H. 2010. Status for sjøfuglene i Norge. Sjøfugl – Speiler havets tilstand – Ottar 5/2010. Ottar 283: 28–35.
  8. Sandvik, H., Erikstad, K.E., Barrett, R.T., Yoccoz, N.G. 2005. The effect of climate on adult survival in five species of North Atlantic seabirds. Journal of Animal Ecology 74(5): 817–831.
  9. Strøm, H. 2006. Black legged kittiwake. In: Kovacs, K. M. and Lydersen, C. (eds.): Birds and Mammals of Svalbard. Tromsø, Norwegian Polar Institute.
  10. Walsh et al. 1995. Seabird monitoring handbook for Britain and Ireland: a compilation of methods for survey and monitoring of breeding seabirds. Published by JNCC / RSPB / ITE / Seabird Group, Peterborough.