Population sizes

Knowledge about the size of seabird populations is important, in part, in order to evaluate the conservation value and vulnerability of the populations. Species that occur in large numbers with a wide distribution are often more robust against negative influences than species that are few in number.

Four main questions

Polarmåke jager lomviGlaucous gull and common guillemots on Bjørnøya (Bear Island). Photo: Kjetil Schjølberg

SEAPOP focuses on four population numbers:

  • How many seabirds breed in Norway?
  • How many seabirds overwinter along the coast?
  • How many sea ducks moult (change feathers) along the coast in autumn?
  • How many seabirds do we find on the open sea during the different seasons?

 

The mapping of birds in the breeding season is used to calculate population sizes of the seabirds. The number of nesting pairs at a given breeding locality is counted, and these numbers are summed up over larger areas. This type of mapping is laborious, and in principle is done only every tenth year. We therefore use data from the nearest monitoring sites to adjust and update the population numbers for every individual breeding locality.

Population numbers only reflect breeding birds

It is important to note that the numbers represent the number of breeding pairs, and therefore the non-breeding portion of the population is not taken into account. This principally includes immature birds and adult birds that choose not to breed.

The population numbers give an updated picture of the abundance of the different species in Norwegian areas. The numbers are used in many connections, and they explain which seabird species dominate the Norwegian sea areas and which species Norway has a special management responsibility for.

Table: Rounded estimats for the number of breeding birds (pairs) in Norwegian areas of responsibility per 2014
SpeciesFastlandetJan MayenSvalbardNorwayNational shareEuropeShare in Norway
North Sea – SkagerrakNorwegian SeaBarents SeaTotalBjørnøyaOther areasTotal
Northern Fulmar1 600 7 500 0 8 000 > 170 000 30 000 < 1 mill. < 1 mill. ± 1 mill. ± 20 % 3 000 000 33 %
European Storm-Petrel1 > 100 > 1 000 > 100 < 10 000 0 0 0 0 < 10 000 < 1 % 690 000 1 %
Leach's Storm-Petrel1 > 10 > 100 0 < 1 000 0 0 0 0 < 1 000 < 1 % 150 000 1 %
Northern Gannet 0 3 600 2 100 5 700 0 > 10 0 10 5 700 < 1 % 300 000 2 %
Great Cormorant2 2 500 13 500 5 500 21 000 0 0 0 0 21 000 < 1 % 45 000 41 %
European Shag 14 000 9 000 5 000 28 000 0 0 0 0 28 000 1 % 81 000 35 %
Common Eider 37 000 41 000 9 000 87 000 < 200 100 17 000 17 000 104 000 2 % 2 000 000 5 %
King Eider 0 0 0 0 0 0 500 500 500 < 1 % 500 100 %
Great Skua < 10 90 20 > 110 < 50 750 250 1 000 1 100 < 1 % 16 000 7 %
Arctic Skua3 < 300 < 1 000 < 1 000 2 000 < 50 100 > 900 1 000 3 000 < 1 % 17 500 17 %
Common Tern1 7 000 < 3 000 1 000 < 11 000 0 0 0 0 < 11 000 < 1 % 300 000 4 %
Arctic Tern1 5 000 20 000 4 000 29 000 < 1 000 < 100 < 10 000 < 10 000 < 40 000 1 % 750 000 5 %
Mew Gull3 5 500 75 000 10 000 90 000 < 5 < 5 0 < 5 90 000 2 % 500 000 18 %
Lesser Black-Backed Gull 21 500 6 500 < 100 28 000 < 50 < 5 0 < 5 28 000 1 % 180 000 16 %
Herring Gull 19 000 42 000 11 500 72 000 < 5 0 0 < 5 72 000 1 % 850 000 8 %
Glaucous Gull 0 0 0 0 > 200 400 3 600 4 000 4 000 < 1 % 21 500 20 %
Great Black-Backed Gull 8 500 30 000 4 500 43 000 < 40 20 80 100 43 000 1 % 120 000 36 %
Black-Legged Kittiwake 6 000 44 000 37 000 87 000 < 10 000 135 000 109 000 245 000 340 000 6 % 2 500 000 14 %
Ivory Gull 0 0 0 0 0 0 2 000 2 000 2 000 < 1 % 2 000 100 %
Common Guillemot 50 2 600 14 000 17 000 < 1 000 132 000 100 132 000 150 000 3 % 2 900 000 5 %
Brünnich's Guillemot 0 0 < 100 < 100 > 110 000 95 000 520 000 615 000 725 000 13 % 1 000 000 73 %
Razorbill 300 < 10 000 < 45 000 < 55 000 < 100 100 20 120 55 000 1 % 500 000 11 %
Little Auk1 0 0 0 0 < 100 000 ± 50 000 > 1 000 000 > 1 000 000 > 1 000 000 ± 20 % > 1 000 000 < 100 %
Black Guillemot4 < 400 15 000 20 000 35 000 < 1 000 < 1 000 19 000 20 000 55 000 1 % 200 000 28 %
Atlantic Puffin 5 000 553 000 907 000 1 465 000 < 5 000 < 1 000 9 000 < 10 000 1 500 000 27 % 5 500 000 27 %
Total 133 000 875 000 1 075 000 2 100 000 400 000 440 000 < 2 500 000 3 000 000 5 500 000 100 % 23 000 000 24 %
  1. Insufficient grounds for good population estimates for this species.
  2. The numbers for Europe and the share in Norway apply to the subspecies P. c. carbo, which breeds in Mid-Norway og North-Norway.
  3. Applies only to the population breeding along the coast. The inland population innlandet has not been assessed.
  4. The species demands special methodology for assessment, and good monitoring sites are lacking. Therefore, the estimate has not been updated since Barrett et al. (2006; Atlantic Seabirds).