| Kingdoms / Animalia / Craniata / Aves / Anseriformes / Anatidae / Mergus / Species |
| < > Mergus merganser - Common merganser (Click photographs/illustrations: full picture & further details) |
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Alternative Names (Synonyms) |
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| Goosander American merganser Fish duck Sawbill Gänsesäger (German) Harle bièvre (French) Serrata grande (Spanish) Mergánsar (Spanish) Grote Zaagbek (Dutch) Storkrake (Swedish) Mergus merganser merganser Eurasian goosander Mergus merganser comatus Oriental goosander Mergus merganser americanus American goosander |
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Names for newly-hatched |
Duckling, downy. |
Names for non-breeding males or other colour-phases |
Eclipse |
Species Author |
Debra Bourne |
Major References |
B1, B2, B3, B6, B8, B19, B25, B26, B27. Aviculture information: |
ORGANISATIONS |
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TAXA Group (where information has been collated for an entire group on a modular basis) |
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Parent Group |
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Specific Needs Group referenced in Management Techniques |
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Aviculture Information |
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Notes |
General information:
(J23.13.w4, J23.13.w8, B7, B29, B40, B94, B129, D1) Species-specific information:
(J23.13.w4, J23.13.w7, B29, B30, B40, B94, B97, B128.w1, B129, D1).) Aviornis UK Ringing Scheme recommended average ring size: N 13.0mm (D8). |
| Individual Techniques linked in Wildpro |
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External Appearance (Morphology)
Measurement & Weight |
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| Length | 21-27 inches 51-68cm (B3); 58-66cm | |
| Adult weight | General | 898-2160g (B1). |
| Male | Average about 1600g (B3). | |
| Female | Average about 1200g (B3). | |
| Newly-hatched weight | -- | |
| Growth rate | -- | |
| Adult | Bill | Male | Red with blackish dorsal stripe (culmen and nail). |
| Variations (If present) | -- | ||
| Eyes (Iris) | Male | Brown. | |
| Variations(If present) | -- | ||
| Juvenile | Bill | Red with blackish dorsal stripe (culmen and nail). | |
| Eyes (Iris) | Brown. | ||
| Adult | Male | Deep red. |
| Variations (If present) | -- | |
| Juvenile | Deep red. | |
Newly-hatched Characteristics |
| General: Upperparts
dark brown, crown to below eyes tawny brown, white patches on wings and back, underparts
white. Blackish line bill to eyes and from below nape to eyes, divided by light tawny ban,
rest of cheeks and sides of neck chestnut. Bill: Yellow-brown. Feet: Yellow-brown. |
Reproductive Season |
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| Time of year | Begins March-May. |
| No. of Clutches | One. Re-nests if clutch lost. |
Nest placement and structure |
| Treehole or other cavity (use nestboxes if provided), down-lining. |
Egg clutches |
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| No. of Eggs | Average | 8-12 (B1). |
| Range | 6-17 (B1); 8-15 (B8). | |
| Egg Description | Ivory to very pale buff. | |
| 30-32 days (B1); 30-35 days (B8). |
| Synchronous. |
| 60-70 days (B1, B8). |
Sexual Maturity |
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| Males | Two years old. |
| Females | Two years old. |
Feeding Behaviour |
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| Adults | Dive from surface (scan with submerged head), occasionally feed on surface. |
| Newly-hatched | -- |
Parental Behaviour |
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| Nest-building | Solitary or in loose groups. Nest prepared by female. |
| Incubation | By female. |
| Newly-hatched | Tended by female, brooded at night when small, sometimes carried on the back. |
| Juveniles | Become independent about fledging time. |
Social Behaviour |
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| Intra-specific | Mainly gregarious. |
| Inter-specific | -- |
Sexual Behaviour |
| Seasonal pair bond, possibly occasional polygamy. |
Predation in Wild |
| -- |
| -- | |
| Circadian | Crepuscular (dawn and evening) feeding. |
| Fish main part of diet, also aquatic invertebrates, amphibians, small mammals and birds. Little plant material. |
| -- |
Distribution and Movement (Migration etc.) |
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| Normal |
Partially migratory: birds from most northerly areas move to lower latitudes. South as far as Mexico, Mediterranean basin, southern areas of former USSR, northern India, south-east Asia. London: In the London Area, "regular winter visitor, very rare in summer." In 2000, seen at 63 sites, with a few tens of birds on some reservoirs in January to march, and December. (J322.65.w1) |
| Occasional and Accidental | Occasionally seen further south. |
| Introduced | -- |
| Clear freshwater lakes, pools, rivers, preferably with trees nearby. Winter large unfrozen lakes, rivers, lagoons, and brackish marshes. |
Intraspecific variation |
| -- |
Conservation Status |
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| Wild Population - (Importance) |
Not threatened (B1). |
| CITES listing | -- |
| Red-data book listing | -- |
| Threats | Persecuted by anglers and fish farmers (B1). |
Captive Populations |
| Fairly scarce in collections (B8). |
| -- |