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Scotland's Marine Atlas: Information for The National Marine Plan

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WATERBIRDS

Scotland's coast is of particular importance for waterbirds and there are a number of sites of international importance for the wintering populations of wildfowl, waders and geese that they support. Some species of wader such as Eurasian oystercatcher ( Haematopus ostralegus), dunlin ( Calidris alpina alpina), common redshank ( Tringa tetanus), ruddy turnstone ( Arenaria interpres) and purple sandpiper ( Calidris maritima) are associated with coastal environments. Many species are long distance migrant visitors that breed in the high Arctic and winter on Scotland's coasts. Wildfowl such as common shelduck ( Tadorna tadorna) and Eurasian teal ( Anas crecca) occur in estuaries whilst species such as common eider ( Somateria mollissima) are found on more open coasts.

Overall waterbird numbers peaked at 120% in 1995/96 in relation to the 1975/76 baseline, since when there has been a gradual decline. The latest indicator for 2008/09 stands at 102%. Wader numbers which peaked at 102% in 1996/97 have shown an increasing rate of decline and are now standing at 70%, the lowest value since the early 1980s. Wildfowl (ducks and swans) numbers have dropped to 95%, the lowest since 1987/88. In contrast, geese numbers have increased significantly since the baseline was established in 1975/76 and are currently showing a 333% increase.

All waders except Eurasian oystercatcher, grey plover ( Pluvialis squatarola) and sanderling ( Calidris alba) have declined in numbers in recent years. There have been long-term declines in seven species, the largest have been seen in dunlin and northern lapwing ( Vanellus vanellus) numbers (-76%) and a further five species stand at below half of the baseline level (i.e. ringed plover ( Charadrius hiaticula), purple sandpiper, ruddy turnstone, common redshank and European golden plover ( Pluvialis apricaria)). The reasons for these declines are still to be fully explained but may be due to redistribution of wintering birds across north-west Europe due to climate change effects.

There is variation in the fortunes of different wildfowl species, eight species show an increase in numbers, with common shelduck and northern pintail ( Anas acuta) reaching their all time highs, whereas seven species have declined (i.e. tufted duck ( Aythya fuligula), greater scaup ( Aythya marila), northern shoveler ( Anas clypeata), mallard ( Anas platyrhynchos), common eider, red-breasted merganser ( Mergus serrator) and common pochard ( Aythya ferina)), the latter four reaching their all time lows.

Wintering waterbirds average WeBS Count (2004/05 to 2008/09)

Wintering waterbirds average WeBS Count (2004/05 to 2008/09)

Count data were obtained from the BTO Wetland Bird Survey.

Purple sandpiper

Purple sandpiper
© John M Baxter

Dunlin feeding

Dunlin feeding
© John M Baxter

Special Protection Areas for wintering waterbirds containing in excess of 10,000 birds ( counts are the 5 year peak winter mean).

SPA Site

WeBS Principal Site 1

WeBS Average Count

Cromarty Firth

Cromarty Firth

32,279

Dornoch Firth and Loch Fleet

Dornoch Firth; Loch Fleet Complex

39,159

Firth of Forth

Forth Estuary

76,981

Firth of Tay & Eden Estuary

Tay Estuary; Eden Estuary

35,884

Loch of Strathbeg

Loch of Strathbeg

66,068

Montrose Basin

Montrose Basin

50,785

Inner Moray Firth

Inner Moray Firth and Inverness Firth

53,947

Moray and Nairn Coast

Moray Firth

11,336

Upper Solway Flats and Marshes

Solway Estuary

107,859

Ythan Estuary, Sands of Forvie and Meikle Loch

Ythan Estuary

16,833

1 The WeBS principal site boundaries may cover a larger area than the SPA site boundary. Full details of SPA site counts are available from BTO and site alerts can be downloaded from http://www.bto.org/volunteer-surveys/webs/webs-alerts-spas

Wintering Waterbird Indicator

Wintering Waterbird Indicator

Abundance of wintering waterbirds in Scotland, 1975/76 - 2008/09

Abundance of wintering waterbirds in Scotland, 1975/76 - 2008/09
Source: Wetland Bird Survey Results ( WeBS)

Coastal Special Protection Areas supporting waterbirds that use the intertidal and sea areas (some sites also support various goose species (*) which are listed for completeness but which tend only to use adjacent coastal habitat for roosting; sites that only support goose species are not included)

Site

Waterbirds features

Cromarty Firth

Wildfowl assemblage

Dornoch Firth and Loch Fleet

Greylag goose*
Eurasian wigeon

Bar-tailed godwit
Waterbird assemblage

East Sanday coast

Purple sandpiper

Ruddy turnstone

Firth of Forth

Red-throated diver
Great crested grebe
Slavonian grebe
Great cormorant
Pink-footed goose *
Common shelduck
Eurasian wigeon
Mallard
Greater scaup
Common eider
Long-tailed duck
Black (common) scoter
Velvet scoter

Common goldeneye
Red-breasted merganser
Eurasian oystercatcher
Ringed plover
Grey plover
Northern lapwing
Dunlin
Bar-tailed godwit
Eurasian curlew
Common redshank
Ruddy turnstone
Waterfowl assemblage

Firth of Tay and Eden Estuary

Great cormorant
Pink-footed goose *
Greylag goose *
Common shelduck
Common eider
Long-tailed duck
Black (common) scoter
Velvet scoter
Common goldeneye

Eurasian oystercatcher
Grey plover
Sanderling
Dunlin
Black-tailed godwit
Bar-tailed godwit
Common redshank
Waterfowl assemblage

Gruinart Flats, Islay

Barnacle goose *
Light-bellied brent goose

Greenland white-fronted goose *

Inner Clyde estuary

Common redshank

Inner Moray Firth

Greylag goose *
Red-breasted merganser

Bar-tailed godwit
Common redshank

Loch of Strathbeg

Whooper swan
Pink-footed goose *
Greylag goose *

Eurasian teal
Common goldeneye
Waterfowl assemblage

Montrose Basin

Pink-footed goose *
Greylag goose *
Common redshank
Eurasian oystercatcher

Red knot
Waterfowl assemblage

Moray and Nairn coast

Pink-footed goose *
Greylag goose *

Common redshank
Waterfowl assemblage

North Uist machair and islands

Barnacle goose *
Ringed plover

Ruddy turnstone

Sieibhtean agus Cladach Thiriodh

Barnacle goose *
Ringed plover

Greenland white-fronted goose *
Ruddy turnstone

South Uist machair and lochs

Ringed plover

Sanderling

Upper Solway Flats and Marshes

Whooper swans
Pink-footed goose *
Barnacle goose *
Common shelduck
Eurasian teal
Northern pintail
Northern shoveler
Greater scaup
Common goldeneye
Eurasian oystercatcher

European golden plover
Grey plover
Red knot
Sanderling
Dunlin
Bar-tailed godwit
Eurasian curlew
Common redshank
Ruddy turnstone
Waterfowl assemblage

Ythan Estuary, Sands of Forvie and Meikle loch

Pink-footed goose *
Waterfowl assemblage

Pressures

Waterbirds face a range of pressures including various climate change related factors such as temperature changes, salinity changes and sea-level rise. There are already indications that these are resulting in changes in the distribution of certain species with a general north-eastwards shift.

Contamination by hazardous substances also poses a threat. Seaduck, divers and grebes are particularly vulnerable to oil pollution and even a relatively small spill can have a significant impact if it occurs in a particularly important area for a given species. The reduction in the enrichment of many estuarine mudflats, in particular as a result of better regulation of sewage discharges and nutrient runoff, has resulted in a decline in the abundance of some species as the productivity of the mudflats has declined.

The removal of prey species either directly through fisheries or incidentally through disturbance to the seabed can result in reduced availability of food for various waterbird species. Habitat damage and loss due to a variety of coastal activities such as coastal defences, land claim, construction of marinas etc. can also have serious impacts on waterbird numbers.