species no. 19: common eider somateria mollissima ... northern britain (except orkney and shetland),

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  • Key concepts of Article 7(4): Version 2008

    Reproduction & Prenuptial Migration * 136 *

    Species no. 19: Common Eider Somateria mollissima Distribution: Holarctic. Breeding at high latitudes across Northern Eurasia and North America and wintering mainly within the breeding range. Six subspecies are known, of which two occur in the European Union. The nominate S. m. mollissima breeds in northern Britain (except Orkney and Shetland), Northern Ireland and on the coasts of North-west Europe, including the Baltic Sea. It winters mainly in the southern Baltic and North Sea area, with small numbers of birds reaching the Bay of Biscay, Central Europe and the West Mediterranean (France and Italy). Somateria m. faroeensis breeds in the Faeroe, Shetland and Orkney Islands. Movements: Partially migratory, wintering at sea in North and Northwest Europe. Many populations are mainly sedentary, but large numbers of birds from Russia and Fennoscandia are migratory, wintering mostly along the North and West coast of Norway, in the southern Baltic Sea and in the Wadden Sea. A few birds winter inland in central Europe and in the west Mediterranean. In Denmark, the main autumn migration occurs in October and November, although some adult females and juveniles arrive in the Wadden Sea as early as September. The return passage begins in late February. The populations breeding in Britain and Ireland are mainly sedentary or dispersive, including S. m. faroeensis. Population size and trends: The European breeding population is estimated at 840,000-1,200,000 pairs (BirdLife Int. 2004A) of which 490,000 – 610,000 pairs breed in the EU (BirdLife Int. 2004B). The overall trend during 1990-2000 was a small increase (BirdLife Int. 2004A). The birds belonging to the nominate race that winter in Europe has been assigned to three sub-populations (from Delany & Scott 2006):

    • The population at Britain and Ireland which numbers 73,000 birds (trend unknown).

    • The Baltic-Wadden sea population comprising 760,000 individuals (decreasing).

    • The Norway and NW Russian population with 300,000-550.000 birds (stable).

    The subspecies S. m. faroeensis numbers 18,000 – 25,500 of which 12,000-13,500 occurs at Shetland and the Orkney islands in the UK (Delany & Scott 2006). This population is believed to be stable. Biological and behavioural aspects: Males tend to remain further north than females and immatures. Most adult males leave the breeding grounds in May and June to form flocks with non-breeding and immature birds. Many males and immatures of the Baltic population undertake a moult migration in late June and July through the western Baltic to the Wadden Sea. Breeding: clutch size: usually 4-6 eggs (1-8, with more than 8 usually 2 females); incubation: 25-28 days; fledging period: 65-75 days; broods one.

  • Key concepts of Article 7(4): Version 2008

    Reproduction & Prenuptial Migration * 137 *

    Movements

    Common Eider Somateria mollissima

    MIGRANT Member State RESIDENT Breeding Passage Wintering

    FI SE EE Few LV Few LT PL SK CZ DK UK IE Few Few DE NL BE LU Few HU AT SI FR Few ES PT IT Few MT GR CY RO BG Few Few Few HR

  • Key concepts of Article 7(4): Version 2008

    Reproduction & Prenuptial Migration * 138 *

    Definition of period of reproduction

    Common Eider Somateria mollissima

    Member State

    Period of reproduction begins with

    Comments References

    FI Occupation breeding sites 1, 2, 3, 4, 5 SE Occupation breeding sites 1, 2, 18 EE Occupation breeding sites LV LT PL Accidental tries of nesting 2, 3 SK CZ DK Occupation breeding sites UK Occupation breeding sites 2 IE Occupation breeding sites 1, 2, 3 DE Occupation breeding sites Nuptial parade before

    occupation of breeding sites

    4

    NL Construction of the nest Construction of nest short before egg laying

    20

    BE LU HU AT SI FR Occupation breeding sites 1, 4, 6 ES PT IT MT GR CY RO BG Occupation of breeding

    sites 6,13

    HR

  • Key concepts of Article 7(4): Version 2008

    Reproduction & Prenuptial Migration * 139 *

    Period of reproduction

    Common Eider Somateria mollissima

    J A N F E B M A R A P R M A Y J U N J U L A U G S E P O C T N O V D E C FI SE EE LV LT PL SK CZ DK UK IE DE NL BE LU HU AT SI FR ES PT IT MT GR CY RO BG HR

    Comments and conclusions 1) The period of reproduction begins with the occupation of the breeding sites. 2) End of period of reproduction ranges from the 3rd decade of July (EE) to the 2nd

    decade of September (UK). Full flight of young birds marks the end of the reproduction period.

  • Key concepts of Article 7(4): Version 2008

    Reproduction & Prenuptial Migration * 140 *

    Prenuptial migration

    Common Eider Somateria mollissima

    Difficulty in identifying the beginning of the period of return to the rearing grounds?

    Member

    State YES NO References

    FI X 1, 2, 3, 4 SE X 1, 9 EE X LV LT PL X 2, 3 SK CZ DK X UK Mixed populations in some areas 1 IE No information DE 3, 4, 10 NL Distinction between local

    movements of large wintering population and returning migrants is difficult to made

    37

    BE LU HU AT SI FR X 2, 4, 6 ES PT IT MT GR CY RO BG No information due to limited

    number of birds 6, 15

    HR Few 9

  • Key concepts of Article 7(4): Version 2008

    Reproduction & Prenuptial Migration * 141 *

    Period of prenuptial migration

    Common Eider Somateria mollissima

    J A N F E B M A R A P R M A Y J U N J U L A U G S E P O C T N O V D E C FI SE EE LV LT PL SK CZ DK UK IE DE NL BE LU HU AT SI FR ES PT IT MT GR CY RO RO BG ? ? HR

    Comments and conclusions

    1) Partially migratory. In DK and SE, there is a mixture of different populations in winter but they are not distinguishable in the field. In DK breeders, non- breeders, late moulting migrants (both from the Baltic) and wintering birds occur in the Wadden Sea from November to April.

    2) Beginning of the prenuptial migration ranges from the 1st decade of February (DE, BE, NL, BG?) to the 2nd decade of March (SE, FI, EE).

  • Key concepts of Article 7(4): Version 2008

    Reproduction & Prenuptial Migration * 142 *

    Species no. 20: Long-tailed Duck Clangula hyemalis Distribution: Long-tailed ducks have a circumpolar distribution. The birds inhabiting northern Europe stay close to the breeding areas (Iceland, Norway) or winter south to the southern North Sea and around the British Isles. Movements: Migratory. Those breeding in Fennoscandia, north European Russia and western Siberia winter over a large area, ranging from coastal North Norway southwest to the British Isles. The majority of this immense population however spends the winter in a small area ranging from the south Baltic Sea to West Denmark and South Sweden. A few thousand reach the Wadden Sea and only stragglers are recorded further south, especially in hard winters. Some of the birds of the large population of Greenland and Iceland reach the west of the British Isles. Population size and trends: The European breeding population amounts to 10,000- 15,000 pairs, excluding Russia which holds about 700,000 pairs (BirdLife Int. 2004A). The European Union breeding population in Finland and Sweden is estimated at 2,500- 4,000 pairs (BirdLife Int. 2004B). The overall trend during 1990-2000 is stable (BirdLife Int. 2004A, 2004B). The winter population in The North Atlantic (mainly along the coast of Norway), the Baltic Sea and North Sea and in central European lakes is estimated at 4,600,000 birds (Delany & Scott 2006). Greenland and Iceland hold 12,000-35,000 breeding pairs and 100,000-150,000 wintering individuals (Delany & Scott 2006). Both winter populations are believed to be stable (Delany & Scott 2006). Biological and behavioural aspects: Breeding: clutch size 6-9 eggs (5-11); incubation 24-29 days; full flight of young birds at 35-40 days; brood one.

  • Key concepts of Article 7(4): Version 2008

    Reproduction & Pr