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Location United Kingdom, East Anglia,South East
Central coordinates 1o 9.92' East  51o 57.40' North
IBA criteria A4i, A4iii, B1i, B2, C3, C4
Area 3,670 ha
Altitude 0 - 15m
Year of IBA assessment 2007

Royal Society for the Protection of Birds



Site description The Stour estuary straddles the eastern part of the Essex/Suffolk border and comprises five main bays, whilst the Orwell is a relatively long and narrow estuary. Both estuaries support extensive mudflats and saltmarshes. The IBA supports important numbers of wintering waders and wildfowl.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Grey Plover Pluvialis squatarola passage  2001-2006  2,329 individuals  good  A4i, B1i, C3  Least Concern 
Grey Plover Pluvialis squatarola winter  2001-2006  3,209 individuals  good  A4i, B1i, C3  Least Concern 
Common Ringed Plover Charadrius hiaticula passage  2001-2006  856 individuals  good  B1i, C3  Least Concern 
Common Redshank Tringa totanus passage  2001-2006  2,013 individuals  good  B1i, C3  Least Concern 
Common Redshank Tringa totanus winter  2001-2006  2,847 individuals  good  B1i, C3  Least Concern 
Black-tailed Godwit Limosa limosa passage  2001-2006  2,123 individuals  good  B1i, C3  Near Threatened 
Black-tailed Godwit Limosa limosa winter  2001-2006  1,901 individuals  good  B1i, C3  Near Threatened 
Eurasian Curlew Numenius arquata passage  2001-2006  1,382 individuals  good  B2  Near Threatened 
Eurasian Curlew Numenius arquata winter  2001-2006  1,791 individuals  good  B2  Near Threatened 
Ruddy Turnstone Arenaria interpres winter  2001-2006  773 individuals  good  A4i, B1i, C3  Least Concern 
Red Knot Calidris canutus winter  2001-2006  6,361 individuals  good  B1i, B2, C3  Least Concern 
Dunlin Calidris alpina passage  2001-2006  5,743 individuals  good  B2  Least Concern 
Dunlin Calidris alpina winter  2001-2006  10,290 individuals  good  B2  Least Concern 
A4iii Species group - waterbirds passage  2001-2006  30,747 individuals  good  A4iii, C4   
A4iii Species group - waterbirds winter  2001-2006  58,573 individuals  good  A4iii, C4   

IBA Monitoring

2007 high unfavourable medium
Population
Good - based on reliable and complete / representative data

Agricultural expansion and intensification marine and freshwater aquaculture - industrial aquaculture likely in short term (within 4 years) small area/few individuals (<10%) moderate to rapid deterioration low
Climate change and severe weather habitat shifting and alteration happening now majority/most of area/population (50-90%) slow but significant deterioration high
Human intrusions and disturbance recreational activities happening now majority/most of area/population (50-90%) slow but significant deterioration high
Human intrusions and disturbance war, civil unrest and military exercises likely in short term (within 4 years) small area/few individuals (<10%) moderate to rapid deterioration low
Natural system modifications other ecosystem modifications happening now majority/most of area/population (50-90%) slow but significant deterioration high
Residential and commercial development housing and urban areas likely in short term (within 4 years) small area/few individuals (<10%) moderate to rapid deterioration low
Transportation and service corridors shipping lanes likely in short term (within 4 years) small area/few individuals (<10%) moderate to rapid deterioration low

Anas acuta Northern Pintail 700 502 individuals 72 near favourable
Tadorna tadorna Common Shelduck 3140 2099 individuals 67 unfavourable
Pluvialis squatarola Grey Plover 1610 2329 individuals 100 favourable
Pluvialis squatarola Grey Plover 3460 3209 individuals 93 favourable
Charadrius hiaticula Common Ringed Plover 925 856 individuals 93 favourable
Charadrius hiaticula Common Ringed Plover 665 346 individuals 53 unfavourable
Tringa totanus Common Redshank 3320 2847 individuals 86 near favourable
Tringa totanus Common Redshank 2210 2013 individuals 92 favourable
Limosa limosa Black-tailed Godwit 1710 2123 individuals 100 favourable
Limosa limosa Black-tailed Godwit 2110 1901 individuals 91 favourable
Numenius arquata Eurasian Curlew 2140 1791 individuals 84 near favourable
Numenius arquata Eurasian Curlew 1530 1382 individuals 91 favourable
Arenaria interpres Ruddy Turnstone 750 452 individuals 61 unfavourable
Arenaria interpres Ruddy Turnstone 850 773 individuals 91 favourable
Calidris canutus Red Knot 3330 6361 individuals 100 favourable
Calidris alpina Dunlin 9150 5743 individuals 63 unfavourable
Calidris alpina Dunlin 24700 10290 individuals 42 unfavourable
Species group - waterbirds A4iii 21552 30747 individuals 100 favourable
Species group - waterbirds A4iii 63037 58573 individuals 93 favourable

Whole area of site (>90%) covered by appropriate conservation designation  A management plan exists but it is out of date or not comprehensive  Substantive conservation measures are being implemented but these are not comprehensive and are limited by resources and capacity  medium 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Orwell Estuary Site of Special Scientific Interest 1,336 protected area contained by site 1,309  
Stour and Orwell Estuaries Birds Directive 3,317 protected area contained by site 3,317  
Stour and Orwell Estuaries Wetlands of International Importance (Ramsar) 3,324 protected area contained by site 3,324  
Stour Estuary RSPB Reserve 505 protected area overlaps with site 400  
Stour Estuary Site of Special Scientific Interest 2,248 protected area contained by site 2,154  
Suffolk Coast and Heaths Area of Outstanding Natural Beauty 40,300 protected area overlaps with site 2,255  

Habitats

IUCN habitat Habitat detail Extent (% of site)
Forest Broadleaved deciduous woodland  -
Grassland Humid grasslands  -
Wetlands (inland) Mud flats and sand flats; Salt marshes; Tidal rivers and enclosed tidal waters  -
Sea Sea inlets and coastal features  -
Coastline Sea cliffs and rocky shores  -

Land use

Land-use Extent (% of site)
agriculture -
fisheries/aquaculture -
nature conservation and research -
urban/industrial/transport -

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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Stour and Orwell Estuaries. Downloaded from http://www.birdlife.org on 26/11/2014

To provide new information to update this factsheet or to correct any errors, please email BirdLife