Black-legged kittiwake
Last updated 20 May 2025
The black-legged 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 constitutes a large proportion of the seabirds, both in terms of biomass and food consumption, and is widespread across Svalbard and the rest of the Arctic.
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 monitoring 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 on Spitsbergen and on Bjørnøya declined in the years leading up to the mid-2000s. Most of the colonies and have since been stable.
(Cite these data: Norwegian Polar Institute (2025). Black-legged kittiwake population size, as percentage of the average in the colony. Environmental monitoring of Svalbard and Jan Mayen (MOSJ). URL: https://mosj.no/en/indikator/fauna/marine-fauna/black-legged-kittiwake/)
Details on these data
| Last updated | 20 May 2025 |
| Update interval | Yearly |
| Next update | April 2026 |
| Commissioning organization | Ministry of Climate and Environment |
| Executive organization | Norwegian Polar Institute |
| Contact persons | Sébastien Descamps Hallvard Strøm |
Method
Monitoring of colonies on Bjørnøya, Alkefjellet (Hinlopen) and five colonies on Spitsbergen Ossian Sarsfjellet (Kongsfjorden), Fuglehuken (Forlandet) and Alkhornet, Tschermakfjellet and Grumant (Isfjorden). 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 are made 1-4 times per season, from late incubating to early rearing period. Counts are made with 10×40 binoculars.
Quality
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
Norwegian Red List status: The black-legged kittiwake on Svalbard is classified as Near Threatened (NT) based on criterion A2 (a 15–30% reduction in population size over the last three generations) in the Norwegian Red List for Species 2021.
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 kittiwake population on Svalbard has shown a complex dynamic over the pat decades. The population increased during the 1990s, followed by a decline in the following decade. From the mid-2000s, most colonies began to increase again and/or stabilize. However, since around 2020, the trend has become more negative for the kittiwake population on Svalbard, with many colonies once again declining. The outbreak of avian influenza, which spread among seabird populations from 2021 onwards, is likely to explain at least part of this decline.
On mainland Norway the species is in steep decline, and black-legged kittiwakes are assessed as Endangered (EN) on the mainland and Near threatened (NT) on Svalbard in the Norwegian Red List for Species 2021.
Causal factors
The reason for the decline in some Svalbard colonies of kittiwakes is not known. Avian influenza has likely had a negative impact on some colonies in recent years.
Consequences
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) and GPS loggers are used to study activity patterns, migration routes and winter ecology.
Relations to other monitoring
Monitoring programme
- SEAPOP – Monitoring and mapping programme for Norwegian seabirds
- Management plan for the Barents Sea (in Norwegian)
International environmental agreements
- None
Voluntary international cooperation
Related monitoring
- SEAPOP – Monitoring and mapping programme for Norwegian seabirds
The SEAPOP programme also collects data on the annual reproduction success of kittiwakes and the diet of kittiwake chicks on Spitsbergen and Bjørnøya.
Further reading
Links
Publications
- Artsdatabanken (2021, 24. november). Norsk rødliste for arter 2021. http://www.artsdatabanken.no/lister/rodlisteforarter/2021.
- Anker-Nilssen, T., & Strøm, H. (2010). Nytt klima for sjøfugl? Sjøfugl – Speiler havets tilstand – Ottar 5/2010. Ottar 283: 73–81.
- Descamps, S., Anker‐Nilssen, T., Barrett, R. T., Irons, D. B., Merkel, F., Robertson, G. J., … & Zelenskaya, L. (2017). Circumpolar dynamics of a marine top‐predator track ocean warming rates. Global Change Biology, 23(9), 3770-3780. https://doi.org/10.1111/gcb.13715
- Descamps, S., & Ramírez, F. (2021). Species and spatial variation in the effects of sea ice on Arctic seabird populations. Diversity and Distributions, 27(11), 2204-2217. https://doi.org/10.1111/ddi.13389.
- Descamps, S., & Strøm, H. (2021). As the Arctic becomes boreal: ongoing shifts in a high‐Arctic seabird community. Ecology 102(11):e03485. https://doi.org/10.1002/ecy.3485.
- 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. https://doi.org/10.3354/meps07126
- 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. https://doi.org/10.1111/j.0021-8901.2004.00966.x.
- Frederiksen, M., Moe, B., Daunt, F., Phillips, R. A., Barrett, R. T., Bogdanova, M. I., … & Anker‐Nilssen, T. (2012). Multicolony tracking reveals the winter distribution of a pelagic seabird on an ocean basin scale. Diversity and distributions, 18(6), 530-542. https://doi.org/10.1111/j.1472-4642.2011.00864.x.
- Lorentsen, S.-H., & Strøm, H. (2010). Status for sjøfuglene i Norge. Sjøfugl – Speiler havets tilstand – Ottar 5/2010. Ottar 283: 28–35.
- 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. https://doi.org/10.1111/j.1365-2656.2005.00981
- Strøm, H. 2006. Black legged kittiwake. In: Kovacs, K. M. and Lydersen, C. (eds.): Birds and Mammals of Svalbard. Tromsø, Norwegian Polar Institute.
- Walsh, P. M., Halley, D. J., Harris, M. P., Del Nevo, A., Sim, I. M. W., & Tasker, M. L. (1995). Seabird monitoring handbook for Britain and Ireland: a compilation of methods for survey and monitoring of breeding seabirds. JNCC/RSPB/ITE/Seabird Group. Published by JNCC / RSPB / ITE / Seabird Group, Peterborough.