The importance of the United Kingdom for wintering gulls: population estimates and conservation requirements

Figures & data

Table 1. The statuses in existing conservation listings of the principal species considered in this article.

Species	UKBAP^1	BoCC^2	BiE2/BiEU^3	AEWA^4
Black-headed Gull		Amber	Non-SPEC^E	B2
Common Gull		Amber	SPEC 2	B2
Lesser Black-backed Gull		Amber	Non-SPEC^E
Herring Gull	argenteus ssp.	Red	Non-SPEC^E	B2
Great Black-backed Gull		Amber	Non-SPEC^E
^1 UKBAP: UK Biodiversity Action Plan species (http://www.ukbap.org.uk/NewPriorityList.aspx).
^2 BoCC: Birds of Conservation Concern (Eaton et al. 2009).
^3 BiE2: Birds in Europe (BirdLife International 2004a)/BiEU: Birds in the European Union (BirdLife International 2004b). SPEC 2 = species with populations concentrated in Europe and with an unfavourable conservation status; Non-SPEC^E = species with populations concentrated in Europe but with a favourable conservation status.
^4 African–Eurasian Waterbird Agreement (AEWA). B2 = species' populations listed in Column B, Category 2, i.e. populations numbering more than around 100 000 individuals and considered to be in need of special attention as a result of (c) showing significant long-term decline (http://www.unep-aewa.org/documents/agreement_text/table1-overview.htm).

Figure 1. Stratification used to generate population estimates of wintering gulls in Great Britain, its constituent countries, Northern Ireland, the Channel Islands and Isle of Man, for the five principal species of gull that winter in the UK. Dark grey = tetrads in the inland high water strata; light grey = tetrads in the inland low water strata; white = tetrads in the inland no water strata. Grey lines indicate regional boundaries used in the stratification: 1 = north and west Scotland; 2 = east Scotland; 3 = southwest Scotland; 4 = northwest England; 5 = northeast England; 6 = Wales; 7 = midlands; 8 = East Anglia; 9 = southwest England; 10 = southeast England; 11 = Northern Ireland; 12 = Isle of Man; 13 = Channel Islands. Black indicates inland and coastal key sites.

Table 2.  Raw count totals of individual gull species, ‘small gulls’, ‘large gulls’ and ‘unidentified’ gulls used to produce population estimates.

Species	Inland	Coastal	Total
Black-headed Gull Chroicocephalus ridibundus	641 395	534 616	1 176 011
Common Gull Larus canus	212 568	198 457	411 025
‘Small gulls’	189 086	126 042	315 128
Lesser Black-backed Gull Larus fuscus	48 219	13 576	61 795
Herring Gull Larus argentatus	82 331	211 211	293 542
Great Black-backed Gull Larus marinus	14 967	17 880	32 847
‘Large gulls’	33 193	32 550	65 743
‘Unidentified’	485	82 304	82 789
Mediterranean Gull Larus melanocephalus	20	258	278
Little Gull Hydrocoloeus minutus	0	11	11
Ring-billed Gull Larus delawarensis	0	3	3
Caspian Gull Larus cachinnans	2	3	5
Yellow-legged Gull Larus michahellis	59	51	110
Iceland Gull Larus glaucoides	12	16	28
Glaucous Gull Larus hyperboreus	8	17	25
Black-legged Kittiwake Rissa tridactyla	0	1 341	1 341
Total	1 222 345	1 218 336	2 440 681

Table 3. Population estimates (with 95% confidence limits in parentheses) for the five principal wintering gull species in Great Britain, its constituent countries, Northern Ireland, the Channel Islands and Isle of Man in 2003/04–2005/06 and in Great Britain and the UK in 1993 (after Burton et al. 2003).

Survey / country	Black-headed Gull	Common Gull	Lesser Black-backed Gull	Herring Gull	Great Black-backed Gull
2003/04 -2005/06
England	1 854 876 (1 796 286–1 922 835)	469 863 (449 287–491 278)	114 369 (107 742–120 437)	362 821 (346 588–379 444)	53 361 (48 884–58 325)
Scotland	199 682 (188 437–211 796)	200 296 (185 410–215 034)	6 510 (5 742–7 294)	273 058 (252 574–293 613)	18 113 (16 751–19 653)
Wales	100 836 (87 741–116 973)	25 133 (21 686–29 121)	3 838 (3 321–4 453)	93 613 (75 238–116 885)	4 365 (3 897–4 852)
Great Britain	2 155 147 (2 093 327–2 225 476)	695 833 (669 581–721 158)	124 654 (118 055–131 148)	729 801 (696 424–762 731)	75 860 (71 209–80 704)
Northern Ireland	44 336 (37 813–51 822)	9 559 (7 464–11 988)	459 (280–552)	13 559 (10 797–16 776)	750 (588–926)
UK (Britain and Northern Ireland)	2 199 483	705 392	125 113	743 360	76 610
Channel Islands	7 565 (5 476–9 438)	7 702 (4 402–12 102)	14 (8–22)	10 828 (7 743–14 594)	732 (479–1 047)
Isle of Man	1 753 (598–3 159)	35 (15–60)	7 (3–12)	10 106 (8 630–11 542)	566 (461–680)
1993
Great Britain	1 682 385	429 331	60 830	376 775	43 108
UK	1 697 797	430 927	60 830	378 748	43 156

Table 4. National and international thresholds (and associated biogeographic population estimates) for the five principal wintering gull species in Great Britain and Northern Ireland used in the identification of important sites.

	1% GB threshold^a	All-Ireland threshold^b	1% international threshold^c	Biogeographic population(s)^c
Black-headed Gull	22 000^d	1 000	42 100^d	3 700 000–4 800 000 (W Europe population)
Common Gull	7 000	500	16 400	1 200 000–2 250 000 (NW and C Europe population)
Lesser Black-backed Gull	1 200	500	5 500^e	530 000–570 000 (subspecies graellsii) 325 000–440 000 (subspecies intermedius)
Herring Gull	7 300	500	10 200^f	1 300 000–3 100 000 (subspecies argentatus) 990 000–1 050 000 (subspecies argenteus)
Great Black-backed Gull	760	500	4 200	330 000–540 000 (N and W Europe population)
^a Thresholds for Great Britain are derived from the new population estimates in Table 3 and are rounded following the conventions of Musgrove et al. (2011a): for populations of 10 001–100 000, thresholds are rounded to the nearest 10; for populations of over 100 000, thresholds are rounded to the nearest 100; for populations of over 1 000 000, thresholds are rounded to the nearest 1 000.
^b There are no all-Ireland population estimates for wintering gulls and thus no 1% thresholds. For Northern Ireland, we thus use the threshold values used to identify important sites presented by Crowe (2005).
^c International importance thresholds and biogeographic population estimates are taken from Wetlands International (2012).
^d For all populations of 2 000 000 or more individuals, the 1% international threshold is set at 20 000, as all sites which regularly hold 20 000 or more waterbirds of any species qualify as wetlands of international importance under Ramsar Criterion 5 (Wetlands International 2012); 20 000 is thus also the maximum national importance threshold (Holt et al. 2012).
^e Threshold for Larus fuscus graellsii used here following Holt et al. (2012).
^f Threshold for Larus argentatus argenteus used here following Holt et al. (2012).

Figure 2. The proportions of the European winter populations of Black-headed Gull (BH), Common Gull (CM), Lesser Black-backed Gull (LB), Herring Gull (HG) and Great Black-backed Gull (GB) held by the UK, incorporating data from the 1993 UK survey (black columns; BirdLife International 2004a), and the increase on these figures suggested by the 2003/04–2005/06 UK survey (grey columns).

Appendix 1. Sites in Great Britain and Northern Ireland supporting gull numbers exceeding the 1% national (italics) or international (bold) importance thresholds for at least one species during Winter Gull Roost Survey counts in 2003/04–2005/06.

Count site	County	Designation^a	BH^b	CM^b	LB^b	HG^b	GB^b
Bartley Reservoir	West Midlands				1 200
Belfast Lough	Antrim	SPA	11 055	553		854
Belvide Reservoir	Staffordshire	SSSI			3 000
Bewl Bridge	Sussex		69 000	75 000
Blashford Lakes (part of Avon Valley (Bickton to Christchurch) SSSI)	Hampshire, Wiltshire	SSSI			1 350
Blithfield Reservoir	Staffordshire	SSSI			2 620
Brogborough No. 1 and Stewartby Clay Pits	Bedfordshire						1 242
Burghfield Gravel Pits and Theale Gravel Pits	Berkshire				6 800
Chelmarsh Reservoir	Shropshire				3 500
Chew Valley Lake	Avon	SPA	29 800	18 200	7 015
Chingford Reservoirs	Greater London, Essex	SSSI	25 600	9 460
Coquet Island	Northumberland	SPA^c,d					980
Cropston Reservoir and Swithland Reservoir (overlaps with Bradgate Park and Cropston Reservoir SSSI)	Leicestershire	SSSI			2 050
Dungeness	Kent	SPA^c,d					1 404
Eye Brook Reservoir	Leicestershire	SSSI		16 100
Firth of Forth/Firth of Forth Islands	Central, Fife, Lothian	SPA^c,d	26 835	14 647		12 313
Grafham Water	Cambridgeshire	SSSI					1 050
Hallington Reservoir	Northumberland			25 000
Haweswater Reservoir	Cumbria			27 986
Hoveringham	Nottinghamshire						1 600
Humber Estuary	Lincolnshire, Yorkshire	SPA	34 118	31 134			2 387
Hurleston Reservoir	Cheshire		20 000
Inner Thames Estuary (overlaps with Thames Estuary and Marshes SPA)	Essex, Greater London, Kent	SPA	43 602		1 898		857
Llys-y-Fran Reservoir	Dyfed						1 500
Loch of Skene	Grampian	SPA^e		17 284
Lound Gravel Pit (part of Sutton and Lound Gravel Pits SSSI)	Nottinghamshire	SSSI					1 176
Lough Foyle	Derry	SPA	1 300	1 050
Lough Neagh and Lough Beg	Antrim, Armagh, Down, Londonderry, Tyrone	SPA^c,d	1 821
Lower Derwent Valley	Yorkshire	SPA					1 041
Minsmere-Walberswick	Suffolk	SPA		8 600
North Norfolk Coast	Norfolk	SPA^c,d	20 075	9 925
Ogston Reservoir	Derbyshire	SSSI					900
Outer Ards	Down	SPA	1 003	1 110		924
Queen Mary Reservoir	Surrey				6 656	8 279
Ribble and Alt Estuaries	Lancashire, Merseyside	SPA^c,d	21 491			19 592
Roadford Reservoir	Devon				3 978
Roughrigg Reservoir	Strathclyde					15 144
Rutland Water	Leicestershire	SPA	21 000	12 080
Severn Estuary	Gloucestershire, Avon, Somerset, Gwent, East Glamorgan	SPA^d	20 080		6 713
South Cerney	Gloucestershire, Wiltshire	SSSI			5 800
South West London Waterbodies (including Wraysbury, Staines, Island Barn, Queen Elizabeth II, Knight and Bessborough Reservoirs)	Surrey	SPA	24 187		1 758
Stanford Reservoir	Leicestershire, Northamptonshire			8 110
Strangford Lough	Down	SPA	3 177	504		1 755
The Wash	Lincolnshire, Norfolk	SPA^d	25 657	7 794		13 189
Tophill Low Reservoir	Yorkshire	SSSI		11 150
Ullswater	Cumbria			11 470
Upper Solway Flats and Marshes	Cumbria, Dumfries and Galloway	SPA		12 486
Westwater	Borders	SPA		10 050
Westwood Great Pool	Hereford and Worcester	SSSI			3 800
^a Count site overlaps wholly or partly with a SPA or SSSI. Note: all non-marine SPAs in the UK are underpinned by component SSSI or, in Northern Ireland, ASSI.
^b Counts are those used for the estimation of species' populations unless superseded by a supplementary count undertaken between November and March, 2003/04–2005/06. Note, counts do not include estimates derived from numbers of ‘small’, ‘large’ or ‘unidentified’ gulls and thus in some cases are minima; some coastal sites were also incompletely counted. BH = Black-headed Gull; CM = Common Gull; LB = Lesser Black-backed Gull; HG = Herring Gull; GB = Great Black-backed Gull.
^c SPA qualifying features include breeding gull species or a breeding seabird assemblage featuring gulls.
^d Qualifying species of a component SSSI include breeding gull species.
^e Qualifying species of a component SSSI include non-breeding gull species.

Appendix 2. Sites in Great Britain and Northern Ireland which held at least 20 000 gulls during Winter Gull Roost Survey counts in 2003/04–2005/06.

Count site	County	Designation^a	Peak total count^b
The Wash	Lincolnshire, Norfolk	SPA^d	124 907
Bewl Bridge	Sussex		103 021
Humber Estuary	Lincolnshire, Yorkshire	SPA	72 188
Chew Valley Lake	Avon	SPA	58 428
Firth of Forth/Firth of Forth Islands	Central, Fife, Lothian	SPA^c,d	57 196
Severn Estuary	Gloucestershire, Avon, Somerset, Gwent, East Glamorgan	SPA^d	56 622
Inner Thames Estuary (overlaps with Thames Estuary and Marshes SPA)	Essex, Greater London, Kent	SPA	50 998
Ribble and Alt Estuaries	Lancashire, Merseyside	SPA^c,d	47 160
Queen Mary Reservoir	Surrey		43 716
North Norfolk Coast	Norfolk	SPA^c,d	42 996
Queen Mother Reservoir	Berkshire		40 500
Chingford Reservoirs	Greater London, Essex	SSSI	36 883
Rutland Water	Leicestershire	SPA	33 501
Mersey Estuary	Cheshire, Merseyside	SPA	32 606
Upper Solway Flats and Marshes	Cumbria, Dumfries and Galloway	SPA	32 322
Hallington Reservoir	Northumberland		32 070
South West London Waterbodies (including Wraysbury, Staines, Island Barn, Queen Elizabeth II, Knight and Bessborough Reservoirs)	Surrey	SPA	30 821
Draycote Water	Warwickshire		29 965
Eye Brook Reservoir	Leicestershire	SSSI	29 404
Haweswater Reservoir	Cumbria		28 880
Ouse Washes (including Mepal Gravel Pit)	Cambridgeshire, Norfolk	SPA	28 877
Ullswater	Cumbria		27 260
Northumbria Coast	Durham, Northumberland, Tyne and Wear	SPA	26 894
Stour and Orwell Estuaries	Essex, Suffolk	SPA	26 613
Lower Derwent Valley	Yorkshire	SPA	26 082
Morecambe Bay	Cumbria, Lancashire	SPA^c,d,e	24 769
Lackford	Suffolk	SSSI	24 698
Poole Harbour	Dorset	SPA^c,d	24 385
Chasewater (Cannock Reservoir)	Staffordshire		23 604
Fletton Brick Pit	Cambridgeshire		22 786
Ferring to Goring	Sussex		21 235
Breydon Water	Norfolk	SPA	20 999
Hurleston Reservoir	Cheshire		20 903
Strathclyde Park Loch	Strathclyde		20 837
Blithfield Reservoir	Staffordshire	SSSI	20 318
South Cerney	Gloucestershire, Wiltshire	SSSI	20 272
Portsmouth Harbour	Hampshire	SPA	20 015
^a Count site overlaps wholly or partly with a SPA or SSSI. Note: all non-marine SPAs in the UK are underpinned by component SSSI or, in Northern Ireland, ASSI.
^b Counts are those used for the estimation of species' populations unless superseded by a supplementary count undertaken between November and March, 2003/04–2005/06. Note, some coastal sites were incompletely counted.
^c SPA qualifying features include breeding gull species or a breeding seabird assemblage featuring gulls.
^d Qualifying species of a component SSSI include breeding gull species.
^e Qualifying species of a component SSSI include non-breeding gull species.

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