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The site was identified as important in 2007 because it was regularly supporting significant populations of the species listed below, meeting ('triggering') IBA criteria.

Populations meeting IBA criteria ('trigger species'):

Species	Current IUCN Red List Category	Season	Year(s)	Population estimate at site	IBA criteria met
Grey Plover Pluvialis squatarola	LC	passage	2001-2006	2,329 individuals	A4i, B1i, C3
Grey Plover Pluvialis squatarola	LC	winter	2001-2006	3,209 individuals	A4i, B1i, C3
Common Ringed Plover Charadrius hiaticula	LC	passage	2001-2006	856 individuals	B1i, C3
Eurasian Curlew Numenius arquata	NT	passage	2001-2006	1,382 individuals	B2
Eurasian Curlew Numenius arquata	NT	winter	2001-2006	1,791 individuals	B2
Black-tailed Godwit Limosa limosa	NT	passage	2001-2006	2,123 individuals	B1i, C3
Black-tailed Godwit Limosa limosa	NT	winter	2001-2006	1,901 individuals	B1i, C3
Ruddy Turnstone Arenaria interpres	LC	winter	2001-2006	773 individuals	A4i, B1i, C3
Red Knot Calidris canutus	NT	winter	2001-2006	6,361 individuals	B1i, B2, C3
Dunlin Calidris alpina	LC	passage	2001-2006	5,743 individuals	B2
Dunlin Calidris alpina	LC	winter	2001-2006	10,290 individuals	B2
Common Redshank Tringa totanus	LC	passage	2001-2006	2,013 individuals	B1i, C3
Common Redshank Tringa totanus	LC	winter	2001-2006	2,847 individuals	B1i, C3
A4iii Species group - waterbirds	n/a	passage	2001-2006	30,747 individuals	A4iii, C4
A4iii Species group - waterbirds	n/a	winter	2001-2006	58,573 individuals	A4iii, C4

The current IUCN Red List category may differ from that which was valid at the time of IBA criteria assessment (2007).

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

Pressure (threats to the trigger species and/or their habitats)
Threat level 1	Threat level 2	Timing	Scope	Severity	Result
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	dams & water management/use - small dams	likely in short term (within 4 years)	small area/few individuals (<10%)	slow but significant deterioration	low
Natural system modifications	other ecosystem modifications	happening now	majority/most of area/population (50-90%)	slow but significant deterioration	high
Pollution	agricultural & forestry effluents - nutrient loads	happening now	small area/few individuals (<10%)	slow but significant deterioration	low
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

Response (conservation actions taken for the trigger species and/or their habitats)
Protected-area designation	Management planning	Other conservation action	Result
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

For more information about IBA conservation status, please click here

Protected area (PA)	PA designation	PA area (ha)	Relationship of PA with IBA	Overlap of PA with IBA (ha)
Wrabness	Local Nature Reserve	27	protected area overlaps with site	0
Suffolk Coast and Heaths	Area of Outstanding Natural Beauty	40,510	protected area overlaps with site	2,255
Stour Estuary	RSPB Reserve	505	protected area overlaps with site	400
Stour Estuary	Site of Special Scientific Interest (UK)	2,247	protected area overlaps with site	2,154
Stour Estuary	Nature Reserve	531	protected area overlaps with site	0
Stour and Orwell Estuaries	Marine Protected Area (OSPAR)	0	protected area overlaps with site	0
Stour and Orwell Estuaries	Special Protection Area (Birds Directive)	3,667	protected area overlaps with site	3,317
Stour and Copperas Woods, Ramsey	Site of Special Scientific Interest (UK)	78	protected area overlaps with site	0
Stour & Orwell Estuaries	Ramsar Site, Wetland of International Importance	3,324	protected area overlaps with site	3,324
Pipers Vale	Local Nature Reserve	20	protected area overlaps with site	0
Pin Mill	Nature Reserve	34	protected area overlaps with site	0
Orwell Estuary	Site of Special Scientific Interest (UK)	1,335	protected area overlaps with site	1,309
Bridge Wood	Local Nature Reserve	31	protected area overlaps with site	0

Habitat (IUCN level 1)	Habitat detail	Extent (% of site)
Forest	Broadleaved deciduous woodland	-
Grassland	Humid grasslands	-
Marine Intertidal		-
Marine Neritic		-
Marine Coastal/Supratidal		-

For more information about the IUCN Habitat classification, please click here.

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

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Recommended citation
BirdLife International (2023) Important Bird Area factsheet: Stour and Orwell Estuaries. Downloaded from http://datazone.birdlife.org/site/factsheet/stour-and-orwell-estuaries-iba-united-kingdom on 02/12/2023.