Key concepts of Article 7(4): Version 2008
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.
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Movements
Common Eider Somateria mollissima
Member MIGRANT RESIDENT State Breeding Passage Wintering FI 9 9 SE 9 9 9 EE 9 9 Few LV 9 Few LT 9 PL 9 9 SK CZ DK 9 9 9 9 UK 9 9 9 9 IE 9 9 Few Few DE 9 9 9 9 NL 9 9 9 9 BE 9 9 LU Few HU AT 9 SI 9 FR Few 9 9 9 ES PT IT Few 9 MT GR CY RO BG Few Few Few HR 9
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Definition of period of reproduction
Common Eider Somateria mollissima
Member Period of reproduction Comments References State begins with 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 4 occupation of breeding sites NL Construction of the nest Construction of nest short 20 before egg laying BE LU HU AT SI FR Occupation breeding sites 1, 4, 6 ES PT IT MT GR CY RO BG Occupation of breeding 6,13 sites HR
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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.
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Prenuptial migration
Common Eider Somateria mollissima
 Difficulty in identifying the beginning of the period of return to the rearing grounds?
Member YES NO References State 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 37 movements of large wintering population and returning migrants is difficult to made BE LU HU AT SI FR X 2, 4, 6 ES PT IT MT GR CY RO BG No information due to limited 6, 15 number of birds HR Few 9
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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).
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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.
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Movements
Long-tailed Duck Clangula hyemalis
Member MIGRANT RESIDENT State Breeding Passage Wintering FI 9 9 9 SE 9 9 9 EE 9 9 LV 9 9 LT 9 9 PL 9 9 SK CZ 9 9 CZ Few? Few? DK 9 9 UK 9 IE 9 DE 9 9 NL 9 9 BE 9 LU Few HU AT Few Few SI FR Few ES PT IT MT GR CY RO BG Few Few HR 9
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Definition of period of reproduction
Long-tailed Duck Clangula hyemalis
Member Period of reproduction Comments References State begins with FI Occupation of breeding 1, 2, 3, 4, 5 sites SE Occupation of breeding 1, 11 sites 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
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Period of reproduction
Long-tailed Duck Clangula hyemalis
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) In the EU, it only breeds in Fennoscandia. 2) The period of reproduction starts with the occupation of the breeding sites. 3) The period of reproduction ends with the full flight of young birds, ranging from the 2nd decade of August (FI) to the 1st decade of September (SE).
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Prenuptial migration
Long-tailed Duck Clangula hyemalis
 Difficulty in identifying the beginning of the period of return to the rearing grounds?
Member State YES NO References FI Partial migrant in the southern sea 1, 2, 3, 4 areas SE X 1, 18 EE LV LT 6 PL X 2 SK CZ Small numbers of wintering and passage birds difficult to distinguish DK 5 UK X 1 IE X 1, 3 DE X 3, 4 NL Few data available 2 BE LU HU AT 13 SI FR X 6 ES PT IT MT GR CY RO BG Small numbers of wintering and 6, 22 passage birds difficult to distinguish. HR Few 9, 17
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Prenuptial migration
Long-tailed Duck Clangula hyemalis
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 AT SI FR ES PT IT MT GR CY RO BG HR
IE - probably only from Iceland/Greenland; BE and CZ - data based on low numbers
Comments and conclusions
1) Migratory, with most birds wintering in the Baltic and Wadden Seas. 2) The period of prenuptial migration starts with the arrival of first migrants in Fennoscandia and departure from wintering grounds elsewhere. 3) The beginning of the prenuptial migration period ranges from the 2nd decade of February (CZ, DE, DK, BG) to the 3rd decade of March (SE, NL, PL, or even later in LV).
Reproduction & Prenuptial Migration * 147 * Key concepts of Article 7(4): Version 2008 Species no. 21:
Common Scoter Melanitta nigra
Distribution: This bird breeds at high latitudes across northern Eurasia. The western Eurasian population is wintering from the Baltic Sea and southern North Sea south along the Atlantic seaboard to Mauritania.
Movements: Migratory. Outside the breeding season this duck is almost exclusively a marine species. Most birds breeding in Fennoscandia and Russia east to the river Lena winter in the western part of the Baltic and off the coast of the Wadden Sea, with only a relatively small number of birds moving further south and west. Birds breeding in Iceland have been recorded south to Iberian Peninsula and even the Azores.
Population size and trends: The European breeding population amounts to 4,000- 11,000 breeding pairs, Russia excluded (where 100,000-120,000 pairs breed)(BirdLife Int. 2004A). The European Union breeding population is estimated at 2,700-5,200 breeding pairs and is almost totally concentrated in Finland and Sweden (BirdLife Int. 2004B). Populations in most European countries were stable during 1990-2000 (BirdLife Int. 2004A).
The population wintering in the Baltic Sea, and along the east Atlantic coast south to Mauritania is estimated at 1,600,000 individuals and stable (Delany & Scott 2006). By far the majority of these birds winter in the waters of EU Member States.
Biological and behavioural aspects: Breeding: clutch size: 6-8 eggs (5-11), more than 11 probably 2 females; incubation: 30-31 days; full flight of young birds at 45-50 days; brood: one.
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Movements
Common Scoter Melanitta nigra
Member MIGRANT RESIDENT State Breeding Passage Wintering FI 9 9 SE 9 9 9 DK 9 9 EE 9 9 LT 9 9 LV 9 9 PL 9 9 SK CZ UK 9 9 9 IE Few 9 9 9 DE 9 9 NL 9 9 BE 9 9 LU Few HU AT Few SI FR 9 9 ES 9 9 PT 9 9 IT Few MT GR CY RO BG Few Few HR 9
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Definition of period of reproduction
Common Scoter Melanitta nigra
Member Period of reproduction Comments References State begins with FI Occupation of breeding 1, 2, 3, 4, 5 sites SE Occupation of breeding 1, 9, 11 sites EE LV LT PL SK CZ DK UK 10 IE Occupation of breeding 1, 4, 6 sites DE NL BE LU HU AT SI FR ES PT IT MT GR CY RO BG HR
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Definition of period of reproduction
Common Scoter Melanitta nigra
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 EU breeding population is almost totally concentrated in FI and SE with less that 200 pairs breeding in IE and UK. 2) The period of reproduction begins with the occupation of the breeding sites. 3) The period of reproduction ends with the full flight of young birds, ranging from the 3rd decade of August (IE, UK) to the 2nd decade of September (SE).
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Prenuptial migration
Common Scoter Melanitta nigra
 Difficulty in identifying the beginning of the period of return to the rearing grounds?
Member YES NO References State FI Small numbers may over-winter in X 1, 2, 3, 4 Åland EE 4 LV LT PL X 2 SK CZ SE X 1, 9 DK 5 UK X 1 IE X 1, 3 DE X 4, 12 NL X 37 BE X 3 LU HU AT SI FR X 6 ES PT Little information available IT Rare and irregular winter visitor 2, 14, 16, 26, 27, 28 (c. 270i) MT GR CY RO BG Very small numbers of wintering 6, 15 and passage birds. HR Few 10, 11, 14
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Prenuptial migration
Common Scoter Melanitta nigra
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) Migratory with most birds that breed in Fennoscandia wintering in the western part of the Baltic and off the coast of the Wadden Sea. 2) The period of prenuptial migration starts with the arrival of first migrants (SE, FI) or the departure from the wintering grounds. 3) The beginning of the prenuptial migration period ranges from the 1st decade of February (IT) to the 1st decade of April (SE).
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Species no. 22:
Velvet Scoter Melanitta fusca
Distribution: The Velvet Scoter super-species can be divided in three subspecies, of which two, collectively named White-winged Scoter, are not considered here as they both breed and winter (far) outside Europe. The Velvet Scoter breeds from North Europe east to the Yenisey River (approximately 85°E) and in small numbers south and east of the Black Sea. The main wintering range extends south to north-western Europe.
Movements: Migratory; birds breeding from Fennoscandia east to Siberia winter mainly in the Baltic Sea, with smaller numbers continuing further (south)west. Following cold weather in northern Europe small influxes can occur on freshwater lakes in Central Europe. The main autumn migration in the Baltic takes place in October and November. The return migration starts late, with large numbers remaining in Danish waters until April. Huge numbers concentrate in the Gulf of Riga in early May, before moving overland to breeding areas in northern Russia.
Population size and trends: The European breeding population is estimated at 85,000 – 100,000 pairs of which 60,000 – 70,000 breeds in Russia (BirdLife Int. 2004A). The breeding population in the EU (Sweden, Finland & Estonia) amounts 25,000 – 31,000 pairs (BirdLife Int. 2004B). A very small breeding population in the Black Sea-Caspian Sea region holds about 80-140 breeding pairs.
The winter population in the Baltic and west Europe is estimated at 1,000,000 birds (Delany & Scott 2006). The majority of these birds winter in the waters of EU Member States, especially in the Baltic Sea.
Biological and behavioural aspects: It winters mostly at sea in shallow water of the littoral zone. It is gregarious outside the breeding season, usually moulting and wintering in large flocks, sometimes of several thousand birds and often in company with M. nigra. In June, most males leave the breeding grounds to moult in large gatherings, mainly along the north coast of Russia, small numbers in Danish waters. Birds are flightless for three to four weeks during the wing moult. Adult females migrate before males.
Breeding: clutch size: usually 7-9 eggs (5-12, more than 12 usually 2 females); incubation: 26-29 days; fledging period: 50-55 days; brood one.
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Movements
Velvet Scoter Melanitta fusca
Member MIGRANT RESIDENT State Breeding Passage Wintering FI 9 9 SE 9 9 9 EE Few 9 9 LT 9 9 LV 9 9 PL 9 9 SK CZ Few DK 9 9 UK 9 9 IE Few DE 9 9 NL 9 9 BE 9 9 LU Few HU AT 9 SI FR 9 9 ES Few PT IT 9 MT GR CY RO BG Few Few HR 9
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Definition of period of reproduction
Velvet Scoter Melanitta fusca
Member Period of reproduction Comments References State begins with FI Occupation breeding sites 1, 2, 3, 4, 5 SE Occupation breeding sites 1, 2, 9 EE Occupation breeding sites 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
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Definition of period of reproduction
Velvet Scoter Melanitta fusca
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) In the EU, it only breeds in FI, SE and EE. 2) The period of reproduction begins with the occupation of the breeding sites. 3) The end of the period of reproduction ranges from the 3rd decade of August (EE) to the 2nd decade of September (SE). Full flight of young birds marks the end of the reproduction period.
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Prenuptial migration
Velvet Scoter Melanitta fusca
 Difficulty in identifying the beginning of the period of return to the rearing grounds?
Member State YES NO References FI To some extent in Åland where X 1, 2, 3, 4 small numbers may over-winter SE X 1, 8 EE X LV LT PL Prenuptial migration without clear 2 peaks. SK CZ X DK No data on migration 5 UK X 1 IE X 1, 3 DE X 4 NL X 37 BE Very small population and 1, 2, 3, 4 presence of wintering birds LU HU AT Small population and irregular presence SI FR Small population; mixing of 2, 4, 6 migrating and wintering birds ES PT IT X MT GR CY RO BG Very small numbers of wintering 6, 15 and passage birds HR Few 9
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Prenuptial migration
Velvet Scoter Melanitta fusca
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) Highly migratory. 2) Arrival of first migrants in SE and FI, and departure from wintering grounds in other countries, corresponds to the beginning of the prenuptial migration. 3) Beginning of prenuptial migration ranges from the 2nd decade of February (SK, BG) to the 2nd decade of April (SE).
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Species no. 23:
Common Goldeneye Bucephala clangula
Distribution: Holarctic, with a wide breeding range across northern Eurasia and North America. The Goldeneye breeds commonly in the coniferous forest zone from western Norway eastwards (north to 55°N). The wintering range of the Palearctic birds extends south to Mediterranean, Black and Caspian Seas, China and Japan. Scattered breeding populations are also found in the Baltic States, Germany, the Czech Republic and Britain (Scotland), and the species has recently colonised Denmark. The species occurs as a rare winter visitor to North Africa during severe winters.
Movements: Migratory, wintering mainly at sea in the northern parts of its winter range but also on large rivers, lakes, reservoirs and coastal lagoons further south, and often far inland (e.g. in Central Europe). Birds breeding in northern Europe winter mainly in the Baltic Sea, Denmark, The Netherlands, Britain and Ireland.
Population size and trends: The European population holds 490,000-590,000 breeding pairs (BirdLife Int. 2004A) of which EU 280,000-360,000 breeds in the EU (BirdLife Int. 2004B). The majority of the EU population breeds in Finland and Sweden. Overall the European population was stable during 1990-2000 (BirdLife Int. 2004A).
Within Europe three main populations are tentatively distinguished, based on the winter distribution (from Delany & Scott 2006):
• Wintering in North-west and Central Europe with 1,000,000-1,300,000 individuals (stable), • Wintering in middle Danube/Adriatic Sea with 200,000 individuals (trend unknown), • Wintering in Black Sea with 60,000 individuals (trend unknown).
Biological and behavioural aspects: Moult gatherings are common, e.g. in Matsalu Bay (Estonia), southern Sweden and Finland. Males arrive at the places from early June, and reach peak numbers in late August, when many adult females arrive. The birds are flightless for three to four weeks during the wing moult. On average, female migrate further than males, and juveniles further than adults do. Breeding: clutch size is usually 8-11 eggs (5-13, up to 22 recorded, but by 2 or more females); incubation: 29-30 days; fledging period: 57-66 days; brood one.
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Movements
Common Goldeneye Bucephala clangula
Member MIGRANT RESIDENT State Breeding Passage Wintering FI 9 9 9 SE 9 9 9 EE 9 9 9 LV 9 9 Few LT 9 9 9 PL Very few 9 9 SK 9 9 CZ 9 9 9 DK 9 9 9 UK 9 9 9 IE 9 9 DE 9 9 9 NL Few 9 9 BE 9 9 LU 9 9 HU 9 9 AT Few 9 9 SI 9 9 FR Few 9 9 ES PT IT 9 9 MT GR 9 9 CY 9 RO Few 9 BG 9 9 HR 9 9
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Definition of period of reproduction
Common Goldeneye Bucephala clangula
Member Period of reproduction Comments References State begins with FI Occupation breeding sites 1, 2, 3, 4, 5 SE Occupation breeding sites 1, 8, 11 EE Occupation breeding sites LV LT Occupation breeding 7 sites, nuptial parade PL Occupation breeding sites Very few breeding pairs 2 in Poland. SK CZ Occupation breeding sites DK Very small numbers 5 UK Occupation breeding sites 1 IE DE Occupation breeding sites Nuptial parade before 3, 4 occupation of breeding sites NL BE LU HU AT SI FR ES PT IT MT GR CY RO BG HR
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Period of reproduction
Common Goldeneye Bucephala clangula
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) In the EU, it breeds in northern MS (FI, SE, DK, DE, UK) but also in small number in southeastern EU. 2) The period of reproduction begins with the occupation of the breeding sites. Pair- formation starts in winter, often continuing during prenuptial migration and at the breeding sites. 3) The end of the period of reproduction ranges from the 3rd decade of July (LV, LT, PL, UK) to the 1st decade of September (SE). Full flight of young birds marks the end of the reproduction period.
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Prenuptial migration
Common Goldeneye Bucephala clangula
 Difficulty in identifying the beginning of the period of return to the rearing grounds?
Member YES NO References State FI Partial migrant in the X 1, 2, 3, 4 southwestern archipelagos and locally in inland waters; small numbers over-winter SE X 1, 11, 18 EE X LV 2 LT Mixing of wintering and passing 5,7 birds PL X 2 SK 3, 8 CZ Overlap of wintering and migrating birds DK 5 UK X 1 IE X 1, 3 DE X 3, 4 NL Distinction between local X 7 movements of large wintering population and returning migrants is difficult to made BE Presence of wintering birds 1, 2, 3, 4 LU Small numbers HU Mixing of wintering and migrating birds AT Overlap with wintering birds 3, 13 SI X FR Small population 2, 4, 6 ES PT IT Little information X
MT GR CY RO 3 BG X 6, 15 HR Mixing of wintering and migrating 15, 17 birds
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Period of prenuptial migration
Common Goldeneye Bucephala clangula
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 beginning of the prenuptial migration is not difficult to identify, except on those regions where resident birds are mixed with wintering birds (BE, AT, CZ, FI). 2) Arrival of first migrants in northern countries (LT, SE, FI) or departure from wintering grounds in other countries, corresponds to the beginning of the prenuptial migration. 3) Beginning of prenuptial migration ranges from the 1st decade of February (PL, SK, CZ, DK, DE, AT, SI, FR and HR) to the 3rd decade of March (LV).
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Species no. 24:
Red-breasted Merganser Mergus serrator
Distribution: This merganser has a wide breeding range across northern Eurasia and North America. The birds wintering in the European Union are believed to belong to three sub-populations, (1) eastern Greenland to Novaya Zemlaya and include the British Isles, (2) Scandinavia, Denmark, northern Germany and the Netherlands and (3) a Russian breeding population wintering in SE Europe.
Movements: Partially migratory. The sub-population of Greenland, Iceland and the British Isles is partly sedentary, the migratory part winter in the British Isles. The sub- population of northern Europe and North-west Russia is migratory and winters from the Baltic Sea to Portugal. The birds occurring in the Black Sea belong to a more eastern population.
Population size and trends: The European breeding population amounts to 73,000- 120,000 pairs (BirdLife Int. 2004A). The European Union breeding population is estimated at 50,000-67,000 pairs (BirdLife Int. 2004B) and is concentrated in Finland (40%) and Sweden (20%) (BirdLife Int. 2004A). Ten other Member States hold small breeding populations.
The European wintering population can tentatively be divided in into two sub- populations (from Delany & Scott 2006):
• The North-west and Central Europe population which holds about 170,000 individuals – trend unknown.
• The Black Sea/East Mediterranean population which holds about 50,000 individuals. Trend for this population is also unknown.
Biological and behavioural aspects: Breeding: clutch size: usually 8-10 eggs (6-14), larger numbers by 2 females; incubation: 31-32 days; full flight of young birds at 60- 65 days; brood one.
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Movements
Red-breasted Merganser Mergus serrator
Member MIGRANT RESIDENT State Breeding Passage Wintering FI 9 9 9 SE 9 9 9 DK 9 9 9 EE 9 9 9 LT Few 9 9 LV 9 9 ? PL Very few 9 9 SK 9 9 CZ Few Few UK 9 9 9 9 IE 9 9 9 9 DE 9 9 9 NL 9 9 9 BE 9 9 LU Occasional HU AT 9 9? SI 9 Few FR Few 9 9 ES 9 PT 9 IT 9 MT GR 9 CY RO 9 9 BG 9 9 HR 9
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Definition of period of reproduction
Red-breasted Merganser Mergus serrator
Member Period of reproduction Comments References State begins with FI Occupation of breeding 1, 2, 3, 4, 5 sites SE Occupation of breeding 1, 2, 11 sites EE Occupation of breeding 4 sites LT Occupation of breeding 7 sites LV 2 PL Occupation of breeding Very few breeding pairs 2 sites SK CZ DK Occupation of breeding sites UK Occupation of breeding 2 sites IE Occupation of breeding Pairs before occupation of 1, 2, 3, 6 sites breeding sites DE Occupation of breeding Nuptial parade before 3, 4, 5 sites occupation of breeding sites NL Construction of the nest 34 BE LU HU AT SI FR ES PT IT MT GR CY RO BG HR
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Period of reproduction
Red-breasted Merganser Mergus serrator
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) In the EU, it almost exclusively breeds in northern countries. 2) The period of reproduction starts with the occupation of the breeding sites. 3) The period of reproduction ends with the full flight of young birds, ranging from the 1st decade of August (UK) to the 1st decade of October (DE).
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Prenuptial migration
Red-breasted Merganser Mergus serrator
 Difficulty in identifying the beginning of the period of return to the rearing grounds?
Member YES NO References State FI X 1, 2, 3, 4 SE X 1, 11, 18 EE X LV 4 LT Mixing of wintering and migrating 5,7 birds PL X 2,3 SK CZ Small numbers of wintering and passage birds difficult to distinguish DK X UK In northern parts of UK, residents 1 & migrants can occur together IE Mixing of wintering & breeding 1, 3 populations in spring DE X 3, 4 NL X 37 BE X 3 LU HU AT 13 SI X FR ES PT Few birds present at any time IT X 2, 14, 16, 26, 27, 28 MT GR CY RO 3 BG X 6, 15 HR X 9, 17
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Period of prenuptial migration
Red-breasted Merganser Mergus serrator
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) Three populations occur in the EU, ranging from partially resident to highly migratory. 2) The prenuptial migration period starts with the arrival of first migrants in northern Europe and departure from wintering grounds in southern Europe. 3) The beginning of the period of prenuptial migration ranges from the 2nd decade of January (BG) to the 3rd decade of March (LT, PL).
Reproduction & Prenuptial Migration * 171 *