|Scientific Name:||Melanitta deglandi|
|Species Authority:||(Bonaparte, 1850)|
|Taxonomic Source(s):||del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Reviewer(s):||Butchart, S. & Symes, A.|
|Contributor(s):||Bowman, T. & Pihl, S.|
|Facilitator/Compiler(s):||Butchart, S., Ekstrom, J., Malpas, L., Taylor, J.|
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). There is uncertainty over the population trend, but any decline is unlikely 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 extremely 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.
|Previously published Red List assessments:|
Native:Canada; Mexico; Saint Pierre and Miquelon; United States
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There is apparently no reliable estimate of this species's total population, and further research is needed.|
Trend Justification: The overall population trend is thought to be negative (Delany and Scott 2006), although there are mixed results from combined scoter Melanitta spp. surveys (T. Bowman in litt. 2012). According to one analysis, this species appears to have undergone a small or statistically insignificant increase over the last 40 years in North America (data from Breeding Bird Survey and/or Christmas Bird Count [CBC] [Butcher and Niven 2007]) Note, however, that these surveys cover less than 50% of the species's range in North America (Butcher and Niven 2007), and CBC data may not be reliable for tracking trends in this species, as it winters predominantly offshore, where a large proportion may not be visible to shore-based observers (T. Bowman in litt. 2012).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|| |
Behaviour This species is highly migratory (del Hoyo et al. 1992, Madge and Burn 1988) and breeds from mid-May onwards (Madge and Burn 1988) in solitary pairs or loose groups (del Hoyo et al. 1992, Kear 2005), occasionally nesting in association with gull or tern colonies (Kear 2005). Non-breeding birds spend the breeding season in flocks on open water (Flint et al. 1984). After breeding (from June onwards [Scott and Rose 1996]) the adults migrate to moulting sites (males travelling and moulting before the females) (Madge and Burn 1988), where they become flightless for 3-4 weeks (Scott and Rose 1996). When moulting and overwintering the species is highly sociable and can occur in large flocks (Madge and Burn 1988, Scott and Rose 1996) of several thousands of individuals (Scott and Rose 1996), although it is more common in small scattered groups of c.100 individuals (Snow and Perrins 1998). The species mainly forages by diving and may feed at depths of 30-40 m during the winter (del Hoyo et al. 1992). Habitat Breeding The species breeds on wooded coastlines (Johnsgard 1978, Kear 2005), small freshwater lakes (del Hoyo et al. 1992, Snow and Perrins 1998, Kear 2005), pools and rivers (Snow and Perrins 1998) in northern coniferous forests (Johnsgard 1978, del Hoyo et al. 1992, Snow and Perrins 1998, Kear 2005), wooded Arctic tundra (del Hoyo et al. 1992, Snow and Perrins 1998) and alpine zones (Snow and Perrins 1998, Kear 2005), especially where there are boulder-covered or small rocky islands available for nesting with extensive herbaceous vegetation, shrubs and low trees (Johnsgard 1978, Kear 2005). Non-breeding The majority winter at sea on shallow inshore coastal waters (Madge and Burn 1988, del Hoyo et al. 1992), especially in estuaries or inlets where there are large mussel-beds (Snow and Perrins 1998). The species may also occur on freshwater lakes and estuaries during migration (Madge and Burn 1988, Kear 2005). Diet Its diet consists predominantly of molluscs, as well as crustaceans, worms, echinoderms (del Hoyo et al. 1992), amphipods, isopods (Kear 2005), small fish, and (in freshwater habitats) adult and larval insects (del Hoyo et al. 1992). The species may also consume plant material on its breeding grounds (del Hoyo et al. 1992) (e.g. leaves and shoots) (Flint et al. 1984). Breeding site The nest is a shallow depression positioned on the ground (del Hoyo et al. 1992) in tall grass, among hummocks or under bushes (Flint et al. 1984), usually within 100 m of open water (occasionally up to 2-3 km away) (Kear 2005). The species usually nests in solitary pairs (del Hoyo et al. 1992, Kear 2005), but it may form loose congregations (del Hoyo et al. 1992) (e.g. on islands [Kear 2005]) with neighbouring nests as close as 3 m apart (Snow and Perrins 1998), and will also nest in association with gull or tern colonies (Kear 2005).
|Systems:||Terrestrial; Freshwater; Marine|
|Continuing decline in area, extent and/or quality of habitat:||Unknown|
|Movement patterns:||Full Migrant|
|Congregatory:||Congregatory (and dispersive)|
Moulting and wintering concentrations of this species are very susceptible to oil spills and other marine pollutants (del Hoyo et al. 1992, Kear 2005) (an oil spill could destroy a large proportion of the global population if it occurred in a key moulting or wintering area [Madge and Burn 1988]). The species is also susceptible to the effects of commercial exploitation of marine benthic organisms and shellfish (Kear 2005), and is threatened by drowning in fishing nets (del Hoyo et al. 1992, Kear 2005). It is threatened by habitat degradation as a result of the human exploitation of natural resources in the taiga and lower tundra regions of its breeding range (Kear 2005). It is susceptible to disturbance from tourism in remote coastal and freshwater habitats in its breeding range (Kear 2005), as well as disturbance from wind farms (wind turbines) (Garthe and Huppop 2004). The species is susceptible to avian influenza, so may be threatened by future outbreaks of the virus (Melville and Shortridge 2006).
|Citation:||BirdLife International. 2016. Melanitta deglandi. The IUCN Red List of Threatened Species 2016: e.T22734194A95077697.Downloaded on 11 December 2016.|
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