Since late 1990'es at least 7 different species
of sea-ducks have dropped by 65% in Northern Europe, according
to an article
"Ducks
are disappearing from our seas" BirdGuides
Weekly Newsletter, May 17th, 2012. The mysterious nature of sea
ducks
and the challenges in monitoring their numbers have meant that
the situation had gone largely unnoticed.
Key
areas for sea-ducks during the winter are the coasts of UK, Netherlands,
Germany and Scandinavia. As an example of the
decline, the Velvet Scoter, Melanitta fusca, have gone
from several thousand to fewer than 100 and Long-tailed Ducks,
Clangula hyemalis, have plummeted tenfold, to fewer than 1.000,
according to counts on the Moray Firth in Scotland.
While smaller species like Steller's Eider, Polysticta stelleri,
have attracted concern since 2000, some of the more shocking
recent declines have been among common and widespread populations
such as the Common Eider,
Somateria
mollissima,
which has halved since 1993, and the Long-tailed Duck, Clangula
hyemalis, which has declined by over 65%.
The causes remain unknown, however, though the widespread nature
of the declines has prompted concern that it is linked to environmental
change across much of the arctic and sub-arctic regions where
most of these species breed.
Till very recently the size and location of the flocks of ducks
that live in shallow seas remained a mystery. Often they're beyond
the
horizon, out of sight of land, so you need to get up in a plane
just to count them. From these surveys observers are finding that
numbers are dropping off the edge of a cliff, yet they still barely
understand the basics like their migration routes, breeding success
or life expectancy in the wild. What is clear is that this problem
of rapid decline is widespread.
Once upon a time there were pesticides causing the eggshells to
be weak, and often eggs were destroyed before hatching.
Male
and female Velvet Scoter, Melanitta fusca
Photo:
www.arthurgrosset.com
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Velvet Scoter, Melanitta fusca - The species is
migratory, congregating on the sea during the winter. Small populations
winter
in the North Sea, in the north-west Mediterranean, the Black Sea
and inland on central European lakes. However, the majority
of birds in Europe winter in the Baltic. These migrate by day
along the Estonian coast in spring. In autumn, the males migrate
nocturnally over the Baltic Sea in July to moult around Denmark.
The females and young then join them to moult about 6 weeks
later. |
Distribution
of the Velvet
Scoter
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Moulting and wintering concentrations of this species
are highly vulnerable to oil spills and other marine pollutants
(an oil spill could
destroy a large proportion of the global population if it occurred
in a key moulting or wintering area). The species is also vulnerable
to the effects of commercial exploitation of marine benthic organisms
and shellfish, and is threatened by drowning in fishing nets.
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 and by lake drainage for irrigation and
hydroelectric power production (Armenia). It is vulnerable to
disturbance
from tourism in remote coastal and freshwater habitats in its
breeding range, as well as disturbance from wind farms (wind turbines).
The species suffers predation from American mink, Neovison vison.
on islands and is also susceptible to avian influenza so may be
threatened by future outbreaks of the virus. The species is hunted
in Denmark.
Hunting in Denmark, number of birds
shot.
|
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2005/6
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2006/7
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2007/8
|
Mallard, Anas platyrhynchos
|
546.300
Sweden 75.000
Norway 25.000
|
513.500
|
545.800
|
Other swimming Ducks
|
129.700
|
110.900
|
108.900
|
Eider
|
62.500
Sweden 900
|
67.000
|
61.800
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Other Diving Ducks
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31.200
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30.500
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34.000
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Source for Hunting in
Denmark: Vildtinformation 2009, Udgivet af Miljøministeriet,
Skov- og Naturstyrelsen
Svenska
Jägareförbundets jaktstatistik för jaktåret
1 juli 2006 till 30 juni 2007: |
Long-tailed
Duck, Clangula hyemalis
Photo: Wolfgang Wander
licensed under the GFDL, http://en.wikipedia.org/wiki/File:Long-tailed-duck.jpg
|
Long-tailed
Ducks, Clangula hyemalis - Large flocks winter in the
Baltic, having moved down the coast from their breeding grounds
in Scandinavia and Arctic Russia. Smaller numbers winter in the
North Sea, off the coasts of Britain and in Skagerak. About 2.
million
birds winters in Gulf of Bothnia and the Baltic Sea. Large numbers
having been wintering further south and west, pass through the
Baltic
in May, returning to their breeding grounds. The birds from Eastern
Siberia and North America, winters along the Pacific Coast and
in
the Northern Atlantic Sea.
Source: Various sources.
Distribution
of the Long-tailed Ducks
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According to monitoring data from the Baltic Sea, where the western
Siberian and northern European populations winter, the population
there decreased by up to 70% between 1995 and 2009.
The species is threatened by wetland habitat degradation and loss
from petroleum pollution, wetland drainage and peat-extraction.
It is also threatened with direct mortality from oil pollution,
drowning through entanglement in fishing nets and from hunting
on migration
routes over certain regions of the Arctic. The species has previously
suffered heavy losses from an outbreak of avian cholera and is
susceptible to avian influenza so may be threatened by future
outbreaks of these diseases. The species is hunted for sport in
Denmark.
The source for these data
comes from BirdLife International 2011. Clangula hyemalis. In:
IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2.
<www.iucnredlist.org>. Downloaded on 18 May 2012. |
.
Before learning of
the Birds and Pesticides Campaign I was unaware that some 672
million birds are directly
exposed to pesticides on farms alone and that nearly 10 percent
of them die. Even more frightening, the most
toxic pesticides to birds-diazinon and chlorpyrifos-are used mainly
in home gardens. Approximately one billion
pounds of pesticides are applied annually in the United States,
with 4.4 billion applications in yards and
gardens.
Birds are particularly susceptible
to backyard pesticides, but the problem is not well documented
because few
scientists can confirm that a bird death is pesticide related.
Testable specimens are difficult to obtain, because
dead birds are often overlooked, eaten by scavengers, crushed
by cars, washed away, or destroyed by bacterial
decay. Evidence of pesticide poisoning is often non-existent.
Source: Pesticides and Birds
By TINA PHILLIPS, http://static.birds.cornell.edu/Publications/Birdscope/Summer2001/pesticides.html
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