Scottish Marine and Freshwater Science Volume 5 Number 12: Strategic assessment of collision risk of Scottish offshore wind farms to migrating birds

4. Results

Seabirds

Coastal strip overlaps

4.1. The overlaps between the coastal strips and flight distribution widths are provided in Tables 6 to 11. These values were used to calculate the proportion of each seabird population which passed through each offshore wind farm.

Table 6 - Proportional overlap between the 'near coast' coastal strips and Scottish offshore wind farms using the uniform flight width distribution

Wind farm	Proportional overlap
	0 - 10 km	0 - 20 km	0 - 40 km	0 - 60 km	1 - 60 km
Beatrice	0	0.309	0.223	0.149	0.151
Moray R3 Telford	0	0	0.335	0.224	0.227
Moray R3 Stevenson	0	0	0.285	0.190	0.193
Moray R3 MacColl	0	0	0.275	0.228	0.232
EOWDC	0.353	0.177	0.088	0.059	0.060
Seagreen Alpha and Bravo	0	0	0.317	0.526	0.535
Inch Cape	0	0.231	0.443	0.295	0.300
Neart na Gaoithe	0	0.236	0.325	0.217	0.220
Argyll Array	0.620	0.810	0.608	0.405	0.412
Islay	0	0.311	0.200	0.134	0.136
Robin Rigg	0.094	0.197	0.152	0.152	0.164

Table 7 - Proportional overlap between the 'mid coast' coastal strips and Scottish offshore wind farms using the uniform flight width distribution

Wind farm	Proportional overlap
	0 - 10 km	0 - 20 km	0 - 40 km	0 - 60 km	1 - 60 km
Beatrice	0	0.309	0.223	0.149	0.151
Moray R3 Telford	0	0	0.335	0.224	0.227
Moray R3 Stevenson	0	0	0.285	0.190	0.193
Moray R3 MacColl	0	0	0.275	0.228	0.232
EOWDC	0.353	0.177	0.088	0.059	0.060
Seagreen Alpha and Bravo	0	0	0.317	0.526	0.535
Inch Cape	0	0.231	0.443	0.295	0.300
Neart na Gaoithe	0	0.236	0.325	0.217	0.220
Argyll Array	0.620	0.810	0.608	0.405	0.412
Islay	0	0.311	0.200	0.134	0.136
Robin Rigg	0	0	0	0	0

Table 8 - Proportional overlap between the 'far coast' coastal strips and Scottish offshore wind farms using the uniform flight width distribution

Wind farm	Proportional overlap
	0 - 10 km	0 - 20 km	0 - 40 km	0 - 60 km	1 - 60 km
Beatrice	1.000	0.361	0.178	0.123	0.125
Moray R3 Telford	0.390	0.554	0.277	0.185	0.188
Moray R3 Stevenson	1.000	0.398	0.199	0.133	0.135
Moray R3 MacColl	1.000	0.747	0.374	0.249	0.253
EOWDC	0.353	0.177	0.088	0.059	0.060
Seagreen Alpha and Bravo	0	0	0.478	0.476	0.484
Inch Cape	1.000	0.714	0.356	0.238	0.242
Neart na Gaoithe	0.760	0.365	0.183	0.122	0.124
Argyll Array	0.620	0.810	0.608	0.405	0.412
Islay	0	0.311	0.200	0.134	0.136
Robin Rigg	0	0	0	0	0

Table 9 - Proportional overlap between the 'near coast' coastal strips and Scottish offshore wind farms using the negative binomial flight width distribution

Wind farm	Proportional overlap
	0 - 10 km	0 - 20 km	0 - 40 km	0 - 60 km	1 - 60 km
Beatrice	0	0.033	0.274	0.312	0.345
Moray R3 Telford	0	0	0.085	0.240	0.253
Moray R3 Stevenson	0	0	0.075	0.207	0.218
Moray R3 MacColl	0	0	0.026	0.127	0.135
EOWDC	0.653	0.405	0.123	0.045	0.035
Seagreen Alpha and Bravo	0	0	0.036	0.188	0.200
Inch Cape	0	0.018	0.279	0.472	0.490
Neart na Gaoithe	0	0.018	0.259	0.402	0.417
Argyll Array	0.289	0.721	0.904	0.794	0.797
Islay	0	0.036	0.260	0.320	0.327
Robin Rigg	0.004	0.143	0.228	0.228	0.248

Table 10 - Proportional overlap between the 'mid coast' coastal strips and Scottish offshore wind farms using the negative binomial flight width distribution

Wind farm	Proportional overlap
	0 - 10 km	0 - 20 km	0 - 40 km	0 - 60 km	1 - 60 km
Beatrice	0	0.033	0.274	0.312	0.345
Moray R3 Telford	0	0	0.085	0.240	0.253
Moray R3 Stevenson	0	0	0.075	0.207	0.218
Moray R3 MacColl	0	0	0.026	0.127	0.135
EOWDC	0.653	0.405	0.123	0.045	0.035
Seagreen Alpha and Bravo	0	0	0.036	0.188	0.200
Inch Cape	0	0.018	0.279	0.472	0.490
Neart na Gaoithe	0	0.018	0.259	0.402	0.417
Argyll Array	0.289	0.721	0.904	0.794	0.797
Islay	0	0.036	0.260	0.320	0.327
Robin Rigg	0	0	0	0	0

Table 11 - Proportional overlap between the 'far coast' coastal strips and Scottish offshore wind farms using the negative binomial flight width distribution

Wind farm	Proportional overlap
	0 - 10 km	0 - 20 km	0 - 40 km	0 - 60 km	1 - 60 km
Beatrice	0.997	0.672	0.226	0.114	0.114
Moray R3 Telford	0.062	0.700	0.628	0.377	0.403
Moray R3 Stevenson	0.997	0.724	0.275	0.134	0.134
Moray R3 MacColl	0.997	0.975	0.690	0.404	0.429
EOWDC	0.653	0.405	0.123	0.045	0.035
Seagreen Alpha and Bravo	0	0	0.118	0.353	0.334
Inch Cape	0.997	0.969	0.653	0.378	0.404
Neart na Gaoithe	0.979	0.672	0.250	0.114	0.114
Argyll Array	0.289	0.721	0.904	0.794	0.797
Islay	0	0.036	0.260	0.320	0.327
Robin Rigg	0	0	0	0	0

Collision mortality estimates

4.2. The annual seabird migration collision mortality estimates obtained using the near, mid and far suites of offshore coastal strips and the uniform and negative binomial flight distributions are provided in Tables 12 to 17 and in Figures 48 to 74, Appendix I.

Table 12 - Annual seabird migration collision estimates at Scottish offshore wind farms derived using the near shore coastal strips and uniform flight distribution

Species	Summed spring and autumn passage population	Annual collision estimates at 98% avoidance using Band CRM Options 1/2/3
		Option 1	Option 2 (95% c.i.)	Option 3 (95% c.i.)
Red-throated diver	20,000	12	10 (7-14)	4 (1-7)
Black-throated diver	2,000	0	0 (0-19)	0 (0-29)
Great northern diver	6,000	4	NA	NA
Fulmar	2,000,000	89	90 (1-10,437)	48 (0-12,772)
European storm petrel	300,000	43	NA	NA
Leach's storm petrel	700,000	105	NA	NA
Northern gannet	1,000,000	3,917	3,064 (-866-6,993)	1,502 (-1,316-4,307)
Great cormorant	17,000	15	NA	NA
European shag	140,000	166	149 (27-789)	27 (4-338)
Arctic skua	15,000	14	11 (0-54)	2 (0-45)
Great skua	60,000	90	78 (19-571)	42 (4-414)
Pomarine Skua	5,000	7	NA	NA
Long-tailed skua	2,000	2	NA	NA
Black-legged kittiwake	2,000,000	7,385	5,300 (2,404-8,195)	1,377 (-33-2,786)
Black-headed gull	240,000	569	504 (22-3,266)	468 (4-3,289)
Common gull	600,000	3,067	2,541 (848-5,447)	1,138 (163-3,382)
Little gull	3,400	4	5 (4-5)	2 (1-2)
Lesser black-backed gull	130,000	817	747 (220-1,575)	363 (52-1,020)
Herring gull	100,000	726	622 (337-1,087)	337 (125-710)
Great black-backed gull	20,000	173	152 (81-268)	78 (31-171)
Little tern	1,200	0	NA	NA
Sandwich tern	8,000	1	3 (0-18)	1 (0-10)
Common tern	40,000	33	30 (14-44)	5 (2-8)
Arctic tern	400,000	94	128 (7-1,028)	41 (2-682)
Common guillemot	4,000,000	8	3 (-2,894-2,900)	1 (-4,159-4,155)
Razorbill	500,000	44	46 (0-3,002)	67 (0-3,987)
Puffin	2,000,000	35	32 (0-2,136)	14 (0-1,344)

Table 13 - Annual seabird migration collision estimates at Scottish offshore wind farms derived using the mid offshore coastal strips and uniform flight distribution

Species	Summed spring and autumn passage population	Annual collision estimates at 98% avoidance using Band CRM Options 1/2/3
		Option 1	Option 2 (95% c.i.)	Option 3 (95% c.i.)
Red-throated diver	20,000	12	10 (7-13)	4 (1-7)
Black-throated diver	2,000	0	0 (0-19)	0 (0-28)
Great northern diver	6,000	4	NA	NA
Fulmar	2,000,000	86	88 (1-10,156)	47 (0-12,480)
European storm petrel	300,000	41	NA	NA
Leach's storm petrel	700,000	100	NA	NA
Northern gannet	1,000,000	3,863	3,051 (-839-6,941)	1,497 (-1,301-4,282)
Great cormorant	17,000	15	NA	NA
European shag	140,000	162	149 (27-782)	27 (4-335)
Arctic skua	15,000	14	11 (0-53)	2 (0-44)
Great skua	60,000	89	77 (19-566)	41 (4-410)
Pomarine Skua	5,000	7	NA	NA
Long-tailed skua	2,000	2	NA	NA
Black-legged kittiwake	2,000,000	7,201	5,244 (2,392-8,095)	1,360 (-22-2,741)
Black-headed gull	240,000	564	501 (22-3,245)	465 (4-3,271)
Common gull	600,000	3,018	2,520 (844-5,394)	1,128 (162-3,349)
Little gull	3,400	3	4 (4-5)	2 (1-2)
Lesser black-backed gull	130,000	804	741 (219-1,559)	360 (52-1,009)
Herring gull	100,000	715	616 (334-1,076)	333 (124-702)
Great black-backed gull	20,000	171	151 (80-265)	77 (30-169)
Little tern	1,200	0	NA	NA
Sandwich tern	8,000	1	3 (0-18)	1 (0-10)
Common tern	40,000	33	30 (14-44)	5 (2-8)
Arctic tern	400,000	92	127 (6-1,008)	41 (2-668)
Common guillemot	4,000,000	8	3 (-2,844-2,849)	1 (-4,081-4,077)
Razorbill	500,000	43	45 (0-2,936)	66 (0-3,910)
Puffin	2,000,000	34	31 (0-2,098)	14 (0-1,309)

Table 14 - Annual seabird migration collision estimates at Scottish offshore wind farms derived using the far offshore coastal strips and uniform flight distribution

Species	Summed spring and autumn passage population	Annual collision estimates at 98% avoidance using Band CRM Options 1/2/3
		Option 1	Option 2 (95% c.i.)	Option 3 (95% c.i.)
Red-throated diver	20,000	16	15 (10-19)	6 (2-10)
Black-throated diver	2,000	0	0 (0-19)	0 (0-36)
Great northern diver	6,000	4	NA	NA
Fulmar	2,000,000	80	82 (1-9,352)	43 (0-11,489)
European storm petrel	300,000	40	NA	NA
Leach's storm petrel	700,000	97	NA	NA
Northern gannet	1,000,000	3,703	2,842 (-801-6,486)	1,422 (-1,212-4,044)
Great cormorant	17,000	208	NA	NA
European shag	140,000	1,272	1,209 (200-6,240)	216 (33-3,246)
Arctic skua	15,000	26	23 (0-107)	5 (0-87)
Great skua	60,000	85	72 (17-534)	38 (4-390)
Pomarine Skua	5,000	7	NA	NA
Long-tailed skua	2,000	2	NA	NA
Black-legged kittiwake	2,000,000	6,502	4,777 (2,184-7,369)	1,243 (-14-2,499)
Black-headed gull	240,000	488	436 (19-2,818)	401 (3-2,826)
Common gull	600,000	7,020	6,660 (2,418-13,761)	2,988 (489-8,629)
Little gull	3,400	10	15 (14-16)	6 (5-7)
Lesser black-backed gull	130,000	1,860	1,924 (615-3,941)	941 (149-2,536)
Herring gull	100,000	1,654	1,571 (874-2,693)	844 (321-1,752)
Great black-backed gull	20,000	391	375 (205-655)	188 (78-405)
Little tern	1,200	5	NA	NA
Sandwich tern	8,000	27	37 (8-343)	18 (3-191)
Common tern	40,000	413	362 (169-534)	60 (19-91)
Arctic tern	400,000	806	1,005 (46-8,876)	363 (16-6,193)
Common guillemot	4,000,000	15	9 (-5,407-5,425)	2 (-7,389-7,370)
Razorbill	500,000	79	84 (0-5,486)	125 (0-7,262)
Puffin	2,000,000	31	29 (0-1,941)	13 (0-1,208)

Table 15 - Annual seabird migration collision estimates at Scottish offshore wind farms derived using the near offshore coastal strips and negative binomial flight distribution

Species	Summed spring and autumn passage population	Annual collision estimates at 98% avoidance using Band CRM Options 1/2/3
		Option 1	Option 2 (95% c.i.)	Option 3 (95% c.i.)
Red-throated diver	20,000	8	8 (5-10)	3 (1-5)
Black-throated diver	2,000	0	0 (0-19)	0 (0-21)
Great northern diver	6,000	4	NA	NA
Fulmar	2,000,000	139	148 (1-16,398)	80 (0-20,188)
European storm petrel	300,000	78	NA	NA
Leach's storm petrel	700,000	190	NA	NA
Northern gannet	1,000,000	3,429	2,569 (-945-6,083)	1,118 (-1,220-3,449)
Great cormorant	17,000	9	NA	NA
European shag	140,000	85	105 (24-471)	22 (4-202)
Arctic skua	15,000	8	7 (0-29)	1 (0-24)
Great skua	60,000	78	68 (17-490)	36 (3-344)
Pomarine Skua	5,000	8	NA	NA
Long-tailed skua	2,000	4	NA	NA
Black-legged kittiwake	2,000,000	10,971	8,532 (3,921-13,144)	2,201 (-22-4,420)
Black-headed gull	240,000	716	656 (29-4,230)	577 (5-4,040)
Common gull	600,000	1,233	1,142 (408-2,370)	483 (84-1,363)
Little gull	3,400	1	1 (1-1)	0 (0-1)
Lesser black-backed gull	130,000	331	334 (107-683)	155 (26-420)
Herring gull	100,000	295	273 (153-467)	144 (58-296)
Great black-backed gull	20,000	71	67 (36-115)	35 (14-74)
Little tern	1,200	0	NA	NA
Sandwich tern	8,000	1	3 (0-16)	1 (0-7)
Common tern	40,000	19	26 (13-37)	5 (2-8)
Arctic tern	400,000	49	94 (6-618)	26 (1-382)
Common guillemot	4,000,000	5	3 (-1,630-1,636)	0 (-2,370-2,371)
Razorbill	500,000	24	25 (0-1,639)	37 (0-2,179)
Puffin	2,000,000	56	52 (0-3,455)	24 (0-2,189)

Table 16 - Annual seabird migration collision estimates at Scottish offshore wind farms derived using the mid offshore coastal strips and negative binomial flight distribution

Species	Summed spring and autumn passage population	Annual collision estimates at 98% avoidance using Band CRM Options 1/2/3
		Option 1	Option 2 (95% c.i.)	Option 3 (95% c.i.)
Red-throated diver	20,000	8	7 (5-10)	3 (1-5)
Black-throated diver	2,000	0	0 (0-19)	0 (0-21)
Great northern diver	6,000	4	NA	NA
Fulmar	2,000,000	135	145 (1-15,972)	78 (0-19,752)
European storm petrel	300,000	75	NA	NA
Leach's storm petrel	700,000	182	NA	NA
Northern gannet	1,000,000	3,347	2,550 (-903-6,004)	1,110 (-1,198-3,411)
Great cormorant	17,000	9	NA	NA
European shag	140,000	85	105 (24-471)	22 (4-202)
Arctic skua	15,000	7	6 (0-29)	1 (0-23)
Great skua	60,000	77	67 (17-481)	36 (3-339)
Pomarine Skua	5,000	8	NA	NA
Long-tailed skua	2,000	3	NA	NA
Black-legged kittiwake	2,000,000	10,694	8,448 (3,902-12,994)	2,175 (-7-4,352)
Black-headed gull	240,000	709	651 (28-4,200)	573 (5-4,013)
Common gull	600,000	1,197	1,126 (406-2,332)	475 (83-1,339)
Little gull	3,400	1	1 (1-1)	0 (0-1)
Lesser black-backed gull	130,000	322	329 (106-671)	152 (26-412)
Herring gull	100,000	287	269 (151-459)	142 (57-290)
Great black-backed gull	20,000	69	66 (36-113)	34 (14-73)
Little tern	1,200	0	NA	NA
Sandwich tern	8,000	1	3 (0-16)	1 (0-7)
Common tern	40,000	19	26 (13-37)	5 (2-8)
Arctic tern	400,000	49	94 (6-617)	26 (1-382)
Common guillemot	4,000,000	4	3 (-1,590-1,596)	0 (-2,314-2,314)
Razorbill	500,000	23	24 (0-1,591)	36 (0-2,123)
Puffin	2,000,000	54	51 (0-3,398)	23 (0-2,136)

Table 17 - Annual seabird migration collision estimates at Scottish offshore wind farms derived using the far offshore coastal strips and negative binomial flight distribution

Species	Summed spring and autumn passage population	Annual collision estimates at 98% avoidance using Band CRM Options 1/2/3
		Option 1	Option 2 (95% c.i.)	Option 3 (95% c.i.)
Red-throated diver	20,000	17	17 (12-22)	7 (2-11)
Black-throated diver	2,000	0	0 (0-19)	0 (0-36)
Great northern diver	6,000	5	NA	NA
Fulmar	2,000,000	131	141 (1-15,517)	76 (0-19,211)
European storm petrel	300,000	74	NA	NA
Leach's storm petrel	700,000	180	NA	NA
Northern gannet	1,000,000	5,184	4,541 (-959-10,041)	2,073 (-1,811-5,932)
Great cormorant	17,000	195	NA	NA
European shag	140,000	1,156	1,072 (181-5,575)	191 (29-2,987)
Arctic skua	15,000	33	30 (0-136)	7 (0-110)
Great skua	60,000	120	112 (29-788)	59 (6-561)
Pomarine Skua	5,000	10	NA	NA
Long-tailed skua	2,000	3	NA	NA
Black-legged kittiwake	2,000,000	10,151	8,234 (3,879-12,589)	2,139 (44-4,230)
Black-headed gull	240,000	666	632 (30-4,037)	553 (5-3,859)
Common gull	600,000	9,630	9,158 (3,332-18,894)	4,123 (685-11,842)
Little gull	3,400	15	22 (20-24)	9 (7-10)
Lesser black-backed gull	130,000	2,548	2,639 (847-5,400)	1,296 (208-3,481)
Herring gull	100,000	2,266	2,153 (1,199-3,685)	1,163 (446-2,406)
Great black-backed gull	20,000	534	513 (280-895)	259 (108-556)
Little tern	1,200	5	NA	NA
Sandwich tern	8,000	26	35 (7-320)	16 (3-179)
Common tern	40,000	385	328 (152-482)	54 (17-82)
Arctic tern	400,000	736	917 (43-8,127)	324 (14-5,642)
Common guillemot	4,000,000	19	13 (-6,833-6,859)	2 (-9,114-9,084)
Razorbill	500,000	100	106 (0-6,917)	155 (0-9,084)
Puffin	2,000,000	52	49 (0-3,349)	23 (0-2,054)

Non-seabird species

4.3. The annual non-seabird migration collision mortality estimates obtained are provided in Table 18. An avoidance rate of 98% was assumed for all species (although it should be noted that SNH recently amended the goose avoidance rate to 99.8%, which reduces the values for geese to 1/10 ^th of those in Table 18). The proportion of birds at potential collision height for each species was taken from the values presented in Wright et al. (2013; Table 3). It is straightforward to calculate collision estimates for alternative values if required: for example, the percentage at PCH used for waders was 25%; if a PCH value of 50% is of interest the collision estimates in Table 18 can simply be doubled.

Table 18 - Annual terrestrial migration collision estimates at Scottish offshore wind farms.

Non seabird species	Combined spring and autumn passage population	Annual collision estimates at 98% avoidance
Whooper swan	44,000	83
Taiga bean goose	700	3
Pink footed goose	720,000	804
Greenland white fronted goose	26,000	23
Icelandic greylag goose	223,000	95
Greenland barnacle goose	116,000	82
Svalbard barnacle goose	66,000	177
Canadian light bellied brent goose	1900	1
Svalbard light bellied brent goose	350	<1
Wigeon	428,000	90
Teal	200,000	39
Pintail	44,000	9
Pochard	12,000	7
Tufted duck	426,000	70
Scaup	16,000	3
Long-tailed duck	30,000	7
Common scoter	200,000	2
Velvet scoter	2,000	1
Hen harrier	1,280	1
Osprey	1,100	6
Kestrel	2,000	3
Corncrake	13,056	38
Oystercatcher	160,000	65
Golden plover	90,000	33
Grey plover	12,000	8
Dotterel	6,000	6
Whimbrel	1,000,000	671
Curlew breeding	232,000	174
Curlew wintering	171,400	207
Black tailed godwit Icelandic	86,000	51
Bar tailed godwit	76,000	70
Turnstone	100,000	30
Ruff	2,600	5
Sanderling	80,000	22
Dunlin ( alpina)	680,000	474
Dunlin ( schinzii)	30,000	18
Dunlin ( arctica)	436,000	139
Red necked phalarope	25	0
Greenshank	1550	1
Wood sandpiper	100	<1
Redshank robusta	280,000	192
Redshank totanus breeding	70,000	78
Redshank totanus passage	50,000	57
Woodcock breeding	68,000	55
Woodcock wintering	1,288,000	767
Snipe	2,000	1