Brünnich’s guillemot (Uria lomvia)

Closeup of a Brünnich’s guillemot on the ocean surface. — Photo: Stein Ø. Nilsen / tromsofoto.net

Last updated 27 June 2022

Since the Brünnich’s guillemot feeds on key species in the ecosystem and is so abundant, it may be a good indicator for the productivity of the ecosystem. The Brünnich’s guillemot makes up the largest proportion of the seabird biomass in the Barents Sea (over 60%). The species is considered as vulnerable (VU) in Svalbard and critically endangered (CR) on the mainlandfor the Norwegian Red List of Species 2021. It is a generalist and an important predator on capelin, polar cod, pelagic amphipods and krill.

What is being monitored?

Size of breeding population

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The figure shows the trend in the breeding population of Brünnich’s guillemots in 7 selected colonies on Spitsbergen, 2 on Bjørnøya and 3 on Jan Mayen. For each colony, the population size is shown as a percentage of the average in the colony during the entire monitoring period. The population has declined in all the monitored colonies on Bjørnøya and Spitsbergen. The decline is around 4% per year, except for Jan Mayen, where the data series are too short to allow interpretations on population size. Because of this, the Brünnich’s guillemot was listed as Near Threatened (NT) on the Norwegian Red List published in 2015, and Vulnerable (VU) in the revision of the Red List in 2021.

Data

Data files

Excel (.xlsx) Comma-separated (.csv) Machine-readable (.json)

Cite these data

Norwegian Polar Institute (2022). Brünnich's guillemot breeding populations, percentage of colony average. Environmental monitoring of Svalbard and Jan Mayen (MOSJ). URL: http://www.mosj.no/en/fauna/marine/brunnichs-guillemot.html

Brünnich's guillemot breeding populations, percentage of colony average
	Unit	Data supplier	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007	2008	2009	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	2020	2021
Diabas	%	Norwegian Polar Institute		118		107		156	129		123		112	135	140		107				126			99	91	91	103	91	92	73	79	73	75	68	74	64	75
Alkhornet	%	Norwegian Polar Institute		95	154		128	154	127	100	132	150	138	161	146		100				137					78	60	66	62	57	75	69	72	67	51	64	61
Sofiekammen	%	Norwegian Polar Institute		115	84	91	137	107	71			120					75
Grumant	%	Norwegian Polar Institute		143		121		119	139		200		156	196							122					78	74	68	69	65	67	70	65	57	63	68	59
Tschermakfjellet	%	Norwegian Polar Institute		166		120		141	117	89	147		110	146			142		83		108					69	80	54	62	38	51	58		49	39	47	49
Fuglehuken	%	Norwegian Polar Institute		155				134	127	149	148	148			174	127	144	130	113	114	109	101	98	68	69	65	64	56	57	49	55	55	48	42	51	51	35
Ossian Sarsfjellet	%	Norwegian Polar Institute		129		113	133	131	122	96	160	188	127	159	142	130	146	107	92	114	100	100	94	87	78	81	88	88	68	66	77	63	60	45	41	37	38
Bjørnøya, southern part	%	Norwegian Polar Institute	89	100	104		128	119	123		112				125	112	109	108	106	101	87	110		91	88	85	90	92	93	87	84	88	60		62	57	63
Bjørnøya, Evjebukta	%	Norwegian Polar Institute	125	112	111		112	106	101		99	99	100	89	94	90	86
Jan Mayen	%	Norwegian Polar Institute																									169	187	136	113	105	95	77	61	58	48	52

Details on these data

Last updated: 28 June 2022
Update interval: Yearly
Next update: April 2023
Commissioning organization: Ministry of Climate and Environment
Executive organization: Norwegian Polar Institute
Contact persons: Hallvard Strøm; Sébastien Descamps

Method

3 counts of each plot (1 count per observer) are made 4–8 times per season, from late incubating to early rearing periods. Counts are made with 10×40 binoculars.

On Spitsbergen, counts are only made in the western part. Results do not necessarily apply to colonies in eastern Spitsbergen; monitoring started in eastern Svalbard in 2015, and there is not enough data yet to assess a trend.

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, and in SEAPOP's databases.

Reference level and action level

Red List status: a 30-50% reduction in the population over the last three generations means that the species qualifies for the category vulnerable (VU) on Svalbard.

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

Status and trend

In all, 142 colonies are known in Svalbard, with a total breeding population estimation of 615,000 pairs. The largest colonies (> 100,000 pairs) are situated in the southeastern part of Spitsbergen (Koval'skifjella and Stellingfjellet) and on Hopen and Bjørnøya. More than 80 % of the Svalbard population breeds within this "triangle".

Following a period of relative stability or increase, the breeding population of Brünnich’s guillemots has been declining by ca 4% per year since the mid-nineties. This decline has been observed in all the monitored colonies on Spitsbergen and Bjørnøya. An equivaltrend has been observed in Finnmark colonies (mainland Norway). Trends for colonies in East-Svalbard are currently unknown.

The Brünnich’s guillemot is listed as vulnerable (VU) in Svalbard on the Norwegian Red List published in 2021.

Causal factors

The cause of the Brünnich’s guillemot decline in Svalbard is likely connected to the warming of oceans in the species’ winter habitats near Iceland and Greenland. Here the warming most likely has led to changes in the food web and different access to prey for the Brünnich’s guillemot.

Brünnich’s guillemots are hunted in Greenland, but the hunting pressure has been decreasing since 2001. Harvesting is therefore probably not causing the recent Brünnich’s guillemot decline in Svalbard. By-catching of guillemots in fishing gear and/or oil pollution may also contribute to the decline in the population.

Consequences

All colonies of Brünnich’s guillemots monitored in Svalbard (western Spitsbergen and Bjørnøya) show signs of decline since the mid-1990s.

The number of breeding birds has declined by approximately 4% per year. This means that the average size of the Brünnich’s guillemot population has probably declined by a third in the last decade, at least on Bjørnøya and western Spitsbergen.

Brünnich’s guillemots play an important role in the ecology of Svalbard through their transport of large amounts of nutrients from the marine environment to the terrestrial environment, when they fertilize local areas of tundra with their guano (excrement). A reduction in the breeding population may thus reduce this nutrition "pump", which may have consequences for the terrestrial environment.

About the monitoring

The Brünnich’s guillemot is one of the most numerous seabirds in Svalbard, and breeds in dense colonies all over the archipelago. The diet of adult Brünnich’s guillemots is more varied than that of common guillemots. It consists mainly of fish and crustaceans, but during the breeding season, chicks are essentially fed with fish, such as polar cod (the most important prey item in Spitsbergen) or capelin (the most important prey item on Bjørnøya).

Brünnich’s guillemots are thus considered to be a good indicator of the availability of pelagic fish stocks. They are also very sensitive to oil spills and by-catching in fishing nets.

Brünnich’s guillemots have shown a drastic decline in population size all over Svalbard since the mid-1990s. The species is now red-listed in Norway (Near Threatened status).

Brünnich’s guillemots are monitored on Bjørnøya and western Spitsbergen since 1988, and in Hinlopen at east Svalbard since 2015. 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 annually. This includes the annual adult survival of Brünnich’s guillemots and annually breeding success.

In each monitored colony, the total number of Brünnich’s guillemots present in some study plots is counted annually. This represents the best and internationnaly accepted method to detect changes in a guillemot colony, and thus the population size.

Places and areas

Fuglehuken is one of the largest Brünnich’s guillemot colony on western Spitsbergen. Ossian Sarsfjellet is located innermost in Kongsfjorden and is easily accessible from Ny-Ålesund. Bjørnøya has one of the largest Brünnich’s guillemot colonies in Svalbard, and the southernmost.

Relations to other monitoring

Monitoring programme: SEAPOP – Monitoring and mapping programme for Norwegian seabirds
International environmental agreements: None
Voluntary international cooperation: CAFF Circumpolar Seabird Group (CBird)
Related monitoring: Pollutants in Brünnich's guillemot; Additional studies (not part of the MOSJ monitoring) have also focused on the winter foraging ecology and migration routes of Brünnich’s guillemots through the use of external loggers (e.g. temperature–depth recorders and geolocators).

Publications

Anker-Nilssen, T., Strøm, H. 2010. Nytt klima for sjøfugl? Sjøfugl - Speiler havets tilstand - Ottar 5/2010. Ottar 283: 73–81.
Descamps, S., Strøm, H., Steen, H. 2013. Decline of an arctic top-predator: synchrony in colony size fluctuations, risk of extinction and the subpolargyre. Oecologia 173(4): 1271–1282.
DOI:10.1007/s00442-013-2701-0
Fluhr, J., Strøm, H., Pradel, R., Duriez, O., Beaugrand, G., Descamps, S. 2017. Weakening of the subpolar gyre as a key driver of North Atlantic seabird demography: a case study with Brünnich’s guillemots in Svalbard. Marine Ecology Progress Series 563: 1–11.
DOI:10.3354/meps11982
Frederiksen, M., Descamps, S., Erikstad, K.E., Gaston, A.J., Gilchrist, H.G., Grémillet, D., Johansen, K.L., Kolbeinsson, Y., Linnebjerg, J.F., Mallory, M.L., McFarlane Tranquilla, L.A., Merkel, F.R., Montevecchi, W.A., Mosbech, A., Reiertsen, T.K., Robertson, G.J., Steen, H., Strøm, H., Thórarinsson, T.L. 2016. Migration and wintering of a declining seabird, the thick-billed murre Uria lomvia, on an ocean basin scale: Conservation implications. Biological Conservation 200.
DOI:10.1016/j.biocon.2016.05.011
Gaston, A.J., Gilchrist, H.G., Hipfner, J.M. 2005. Climate change, ice conditions and reproduction in an Arctic nesting marine bird: Brunnich's guillemot (Uria lomvia L.). Journal of Animal Ecology 74(5): 832–841.
DOI:10.1111/j.1365-2656.2005.00982.x
Irons, D.B., Anker-Nilssen, T., Gaston, A.J., Byrd, G.V., Falk, K., Gilchrist, G., Hario, M., Hjernquist, M., Krasnov, Y.V., Mosbech, A., Olsen, B., Petersen, A., Reid, J.B., Robertson, G.J., Strøm, H., Wohl, K.D. 2008. Fluctuations in circumpolar seabird populations linked to climate oscillations. Global Change Biology 14(7): 1455–1463.
DOI:10.1111/j.1365-2486.2008.01581.x
Kålås et al. (eds.) 2010. The 2010 Norwegian Red List for Species. Norwegian Biodiversity Information Centre.
Lorentsen, S.-H., Anker-Nilssen, T., Strøm, H. 2010. Bestandsutvikling hos sjøfugl. Pp. 38–46 in: Sunnana, K., Fossheim, M., Olseng, C.D. (eds.): Forvaltningsplan Barentshavet – rapport fra overvakingsgruppen 2010. Fisken og havet 1b-2010. Institute of Marine Research (IMR).
Lorentsen, S.-H., Strøm, H. 2010. Status for sjøfuglene i Norge. Sjøfugl - Speiler havets tilstand - Ottar 5/2010. Ottar 283: 28–35.
Strøm, H., Bangjord, G. 2004. Birds and mammals of Svalbard. Pp. 123–137 in: Prestrud, P., Strøm, H., Goldman, H.V. (eds.): A catalogue of the terrestrial and marine animals of Svalbard. Norwegian Polar Institute.
Strøm, H. 2006. Brünnich's guillemot. In: Kovacs, K.M. & Lydersen, C. (eds.): Birds and mammals of Svalbard. Tromsø, Norwegian Polar Institute.
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.
DOI:10.1111/j.1365-2656.2005.00981
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.