| Kingdom | Phylum | Class | Order | Family |
|---|---|---|---|---|
| ANIMALIA | CHORDATA | AVES | ANSERIFORMES | ANATIDAE |
| Scientific Name: | Mergellus albellus | |||
| Species Authority: | (Linnaeus, 1758) | |||
Common Name/s:
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| Red List Category & Criteria: | Least Concern ver 3.1 | ||||||
| Year Assessed: | 2009 | ||||||
| Assessor/s: | BirdLife International | ||||||
| Reviewer/s: | Bird, J., Butchart, S. | ||||||
| Contributor/s: | Pihl, S. | ||||||
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Justification: This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern. |
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| History: |
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| Countries: |
Native:
Afghanistan; Albania; Austria; Azerbaijan; Belarus; Belgium; Bosnia and Herzegovina; Bulgaria; Canada; China; Croatia; Czech Republic; Denmark; Egypt; Estonia; Finland; France; Germany; Greece; Hungary; India; Iran, Islamic Republic of; Iraq; Ireland; Italy; Japan; Kazakhstan; Korea, Democratic People's Republic of; Korea, Republic of; Kyrgyzstan; Latvia; Liechtenstein; Lithuania; Luxembourg; Macedonia, the former Yugoslav Republic of; Moldova; Mongolia; Montenegro; Nepal; Netherlands; Norway; Pakistan; Poland; Romania; Russian Federation; Russian Federation; Russian Federation; Serbia; Slovakia; Slovenia; Spain; Sweden; Switzerland; Syrian Arab Republic; Taiwan, Province of China; Tajikistan; Turkey; Turkmenistan; Ukraine; United Kingdom; United States; Uzbekistan
Vagrant:
Algeria; Cyprus; Gibraltar; Hong Kong; Iceland; Israel; Jordan; Libyan Arab Jamahiriya; Malta; Myanmar; Palestinian Territory, Occupied; Portugal; Saudi Arabia; Tunisia
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| Range Map: | Click here to open the map viewer and explore range. |
| Habitat and Ecology: | Behaviour This species is highly migratory1, often resting and feeding on inland waterbodies when on passage2. It arrives on the breeding grounds from April2 or early-May and breeds from mid-May onwards3 in single pairs or loose groups1. Males gather in large flocks close to the breeding grounds after mating to undergo a flightless moulting period3. The species then leaves the breeding grounds in early-September and October2, 3. Outside of the breeding season the species is highly gregarious and occurs in small or large flocks2 usually not exceeding 100 individuals, although larger gatherings may form at major passage waters during migration3 and flocks of over 10,000 have been recorded during the winter2. The species feeds diurnally3 by diving to depths of 1-4 m2 and forms gregarious nocturnal roosts2. Habitat Breeding It breeds on freshwater oligotrophic lakes, pools1, 2, oxbow lakes2, backwaters of large slow-flowing rivers1, 2, 5, muskegs (bogs)1, 2 and flooded riverside woods4, 5 in the coniferous and mixed deciduous/evergreen forest zones1, 5. It shows a preference for shallow water4 up to 4 m2 (maximum 6 m) deep5, and requires mature broadleaved trees (e.g. oaks, willows and aspens) with holes in which to nest4. Non-breeding The species overwinters on large freshwater lakes1 and reservoirs4, ice-free rivers2, brackish coastal lagoons, estuaries1 and sheltered coastal bays3 (although rarely on the open sea)1, often resting and feeding on small bodies of water or small streams when on passage2. Diet During the breeding season its diet consists predominantly of benthic aquatic invertebrates such as adult and larval insects1, 2, crustaceans, molluscs and polycheate worms2, as well as amphibians1, fish2 and plant matter1 (seeds, leaves and roots)2. During the winter and in early spring however the species mainly feeds on fish1. Breeding site The species nests in tree hollows1 up to 10 m or more above the ground2 (especially those excavated by Black Woodpeckers Dryocopus martius)3 in mature broadleaved trees (e.g. oak, willow or aspen)4. It may also nest in artificial nest boxes1, 2, especially those erected to attract Common Goldeneye Bucephala clangula3, 5. |
| Systems: | Terrestrial; Freshwater; Marine |
| Major Threat(s): | Where it occurs in large numbers on coastal waters the species is particularly vulnerable to oil pollution1. Populations declined in Europe throughout the 19th and 20th centuries due to habitat degradation and loss (e.g. the loss of mature trees in river valleys as a result of logging, conversion to agriculture and river canalisation)2. The species has also suffered local declines as a result of predation by American mink Neovison vison2, and is susceptible to avian influenza so may be threatened by future outbreaks of the virus6. Utilisation The species is susceptible to a certain amount of hunting pressure when on passage and during the winter1. |
| Citation: | BirdLife International 2009. Mergellus albellus. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 04 February 2012. |
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