SOTEAG ORNITHOLOGICAL MONITORING PROGRAMME

2014 SUMMARY REPORT

Martin Heubeck and Mick Mellor, Aberdeen Institute of Coastal Science and Management, University of Aberdeen.

January 2015

CONTENTS

Page 2014 Executive Summary 2

1. Monitoring of cliff-breeding seabirds 1.1. Weather 4 1.2a. Northern Fulmar Fulmarus glacialis: Population counts 5 1.2b. Northern Fulmar Fulmarus glacialis: Breeding success 6 1.3a. European Shag Phalacrocorax aristotelis: Population counts 8 1.3b. European Shag Phalacrocorax aristotelis: Breeding success 10 1.4a. Black-legged Kittiwake Rissa tridactyla: Population counts 12 1.4b. Black-legged Kittiwake Rissa tridactyla: Breeding success 13 1.5a. Common Guillemot Uria aalge: Population counts 16 1.5b. Common Guillemot Uria aalge: Breeding success and chick diet at Sumburgh Head 18 1.5c. Common Guillemot Uria aalge: Breeding success at Burravoe, Yell 23 1.6a. Razorbill Alca torda: Population counts 24 1.6b. Razorbill Alca torda: Breeding success at Sumburgh Head 25

2. Pre-breeding counts of Black Guillemots Cepphus grylle 26

3. Moulting Common Eiders Somateria mollissima in Yell Sound and Sullom Voe 29

4. Winter counts of seaduck and diving seabirds 4.1. Yell Sound and Sullom Voe 30 4.2. Hascosay, Bluemull and Colgrave Sounds (HBC), and South Unst 33 4.3. Rova Head to Kirkabister, East Mainland 34 4.4. Bressay Sound and North Bressay 35 4.5. Whiteness Voe to Skelda Voe, West Mainland 36 4.6. Vaila Sound and Gruting Voe, West Mainland 37

5. Beached Bird Surveys 5.1. Incidence of oiling 38 5.2. Non-oiled mortality 40

6. 2014 Publications and Presentations 43

7. Acknowledgements 43

Appendix. Seabird monitoring on Foula in 2014 44

1 2014 Executive Summary

1. Monitoring of cliff-breeding seabirds

Northern Fulmar Fulmarus glacialis. There was a 10% increase since 2013 in apparently occupied sites at Troswick Ness, but little change at the three other colonies monitored (Sumburgh Head, Esha Ness, Burravoe). Breeding success at these colonies was slightly lower than in 2013, but still relatively high.

European Shag Phalacrocorax aristotelis. There was a reversal of the non-breeding prevalent in southeast Mainland in 2011-13. Counts of nests at Sumburgh Head and between Virkie and Mousa were 69% higher than in 2013, but still 52% lower than in 2010. There were 27% fewer nests at Papa Stour than in 2006. In breeding success plots, a high percentage of nests progressed to incubation and breeding success was high (1.22 fledged per laying pair at Sumburgh, 1.56 at Burravoe).

Black-legged Kittiwake Rissa tridactyla. A total of 811 nests were counted at 13 extant and former breeding stations around south Mainland, 10% more than in 2012/13 (734) but 40% fewer than in 2009/10 (1,344). A count of 361 nests at Foula was also 10% higher than in 2013 (327) and 38% lower than in 2010 (582). There were 35 nests at Papa Stour, 57% than on the last count in 2006. Breeding success at six colonies averaged 0.91 ± 0.19 SE, the highest figure since 2005 and well above the long-term average.

Common Guillemot Uria aalge. The population index at four colonies was 37% higher than in 2013, probably reflecting higher colony attendance in 2014. At Sumburgh Head, median laying date was three days earlier than in 2013, hatching success of first eggs was relatively high, high colony attendance by adults aided chick survival, and breeding success at 0.54 fledged per laying pair was identical to the 1989-2013 average. Chick diet was 25% sandeels and 70% gadids, most of the latter being small Saithe. At Burravoe, hatching success and chick survival were high, and breeding success was 0.61 per laying pair.

Razorbill Alca torda. A 43% increase in the population index probably reflected low colony attendance in 2013; the total number of birds counted in plots at four colonies (112) was 70% lower than in 2000 (381). At Sumburgh Head, breeding success (0.52) was markedly higher than in 2013 (0.23).

2. Pre-breeding counts of Black Guillemots Cepphus grylle A total of 1,604 adults were counted along nine sections of coast, 10% fewer than in 2012/13 (1,791). Numbers were lower at eight of the nine sections, and at many individual colonies, and it was felt that a genuine reduction in the adult population had occurred, albeit slight. Beached bird survey data suggested that mortality in the January and February gales was higher than average for recent winters.

3. Moulting Common Eiders Somateria mollissima in Yell Sound and Sullom Voe Counts from land and sea on 20-21st August located 210 birds, 151 at aquaculture sites in southern Yell Sound and 59 in Sullom Voe, markedly fewer than the totals of 612 in 2013 and 583 in 2012.

4. Winter counts of seaduck and diving seabirds Complete coverage by boat on 9-10th January of the inshore waters of Yell Sound and Sullom Voe recorded 3,794 seaduck and diving seabirds, including 94 Common Eider, 106 Long-tailed Duck, 282 Red-breasted Mergansers, 25 Great Northern Divers, 58 Slavonian Grebes, 486 Cormorants, 1,436 Shags and 1,216 Black Guillemots. Counts were also made in February of five other standard inshore recording areas.

6. Beached Bird Surveys Eleven oiled seabirds were found (six Fulmars, singles of Gannet, Shag, Lesser Black-backed Gull, Herring Gull and Razorbill), 0.9% of the total and the lowest incidence since 2005; all were very lightly contaminated. Oil on one Fulmar and the Shag was fuel, while another Fulmar was oiled with Russian crude and the Lesser Black-backed Gull with East Shetland Basin crude. January and February were particularly stormy and the incidence of Common Guillemots in February and March was higher than in the previous eight winters. Numbers of Shags and Black Guillemots were also above average for the time of year.

In summary, there was no evidence that the operation of the Sullom Voe Terminal, or its associated tanker traffic, had any detrimental impact on Shetland’s seabird populations during 2014.

2 1. Monitoring of cliff-breeding seabirds

1.1. Weather Weather can influence the ability to carry out seabird monitoring, and in extreme cases, can directly affect seabirds’ breeding success.

Frequent changes in wind direction during April kept the sea disturbed on both the east and west coasts of Shetland, even when blowing offshore, and limited the number of second counts that could be made of Black Guillemot monitoring coastal sections. Cold, windy weather around 9-12th May coincided with the onset of Common Guillemot laying and made confirming new eggs difficult, as birds were sitting very tightly. Several spells of very heavy rain later in the month caused surprisingly few problems for the Common Guillemots, but almost certainly flooded some Razorbill nest sites. Counts in study plots were started a day earlier than usual, on 31st May, taking advantage of a calm day ahead of a forecast of strong south-easterly winds during the first few days of June. Two spells of calm weather, on 14-16th and 22-23rd June, allowed five days of Zodiac work counting Shags and Kittiwakes. July was a particularly foggy month, which caused no apparent problems for breeding seabirds but hampered checks of the breeding success plots on a number of days. The most extreme weather event of the summer was torrential rain throughout 9th August. This had been well-forecast and the Shag success plots at Sumburgh Head were checked on 8th and again on 10th August; amazingly, no chicks were missing or dead on 10th and the only change was that three nests marked as incubating on 8th had become empty/trace on 10th. In summary, weather events appeared to have had little impact on seabird breeding success in 2014.

Table 1.1. Details of observer, date, time, weather and sea conditions for study plot counts of Fulmars, Common Guillemots and Razorbills at four colonies in June 2014.

Sumburgh Head Observer: Martin Heubeck Date Time (BST) Wind Sea state Cloud cover 31st May 2014 1300-1500 SW 1-2 Calm 6/8 5th June 2014 1300-1500 ENE 4 Moderate swell 2/8 7th June 2014 1300-1500 L&V 1-2 Calm 2-3/8 9th June 2014 1300-1500 SSE 3 Slight swell 2/8, very warm 13th June 2014 1300-1450 NE 1 Calm 8/8

Troswick Ness Observer: Martin Heubeck Date Time (BST) Wind Sea state Cloud cover 31st May 2014 1000-1145 Calm Calm 8/8 5th June 2014 1000-1115 ENE 4 Moderate swell 6/8 7th June 2014 1000-1125 E 1 Calm 8/8, very low cloud 9th June 2014 1000-1130 SSE 3 Slight swell 1/8 11th June 2014 1000-1120 SW 4 Moderate swell 7/8

Esha Ness Observer: Mick Mellor Date Time (BST) Wind Sea state Cloud cover 31st May 2014 1300-1400 SW 1 Slight swell 8/8 3rd June 2014 1230-1330 SE 5 Moderate swell 8/8 6th June 2014 1315-1415 NW 1 Moderate swell 8/8 10th June 2014 1240-1330 ESE 4-5 Moderate swell 8/8 13th June 2014 1315-1400 NW 3 Slight swell 8/8

Burravoe, Yell Observer: Mick Mellor Date Time (BST) Wind Sea state Cloud cover 1st June 2014 1005-1045 SE 3 Calm 6/8 5th June 2014 1000-1030 NE 3 Slight swell 3/8 7th June 2014 1025-1130 Calm Calm Fog 11th June 2014 0950-1030 NW 1 Calm 8/8 13th June 2014 0950-1030 Calm Calm 8/8

3 1.2a. Northern Fulmar Fulmarus glacialis: Population counts

There was little change since 2013 in the number of adults or apparently occupied sites (AOS) in study plots, except for a 9-10% increase in both at Troswick Ness, with little overlap in the 2013 and 2014 counts of both parameters (Table 1.2). Counts were within recommended weather conditions except at Esha Ness on 3rd June (wind SE 5) and 10th June (ESE 4-5; Table 1.1), when numbers of adults and AOS were the lowest in the series. The steady increase in the Shetland Fulmar population during the 1980s and early 1990s halted in 1996-2000 (the Scottish population index also peaked in 1996; JNCC 2014), and numbers have fluctuated in the past decade, at around double those in the baseline year of 1978 at Burravoe, around 40-50% higher at Sumburgh Head and Troswick Ness, but only 10-20% higher at Esha Ness (Figure 1.1).

Table 1.2. Mean counts of Fulmars and apparently occupied sites (AOS) at four Shetland colonies, 2013- 2014. Statistics: number of counts, range, mean, standard deviation, coefficient of variation, % change since 2013, and population indices for AOS (1978 = 100).

Colony Unit Year n Range Mean SD CV % ch. Index Sumburgh Birds 2013 5 280-299 290.6 9.81 0.03 Head 2014 5 276-337 294.0 24.57 0.08 +1.4 AOS 2013 5 209-233 220.8 10.50 0.05 150.50.08 2014 5 197-238 223.2 16.02 0.07 +1.1 152.1

Troswick Birds 2013 5 994-1089 1051.2 36.33 0.03 Ness 2014 5 1086-1211 1150.4 50.81 0.04 +9.4 AOS 2013 5 765-838 812.2 29.94 0.04 131.6 2014 5 838-925 890.4 32.10 0.04 +9.6 144.2

Esha Ness Birds 2013 5 341-393 370.8 23.21 0.06 2014 5 273-433 356.2 66.96 0.19 -3.9 AOS 2013 5 240-273 257.0 11.77 0.05 106.9 2014 5 243-289 262.4 21.48 0.08 +2.1 109.2

Burravoe Birds 2013 5 213-236 227.4 9.18 0.04 2014 5 228-259 242.0 13.06 0.05 +6.4 AOS 2013 5 181-191 186.4 3.85 0.02 200.2 2014 5 185-210 196.4 11.15 0.06 +5.4 210.9

Figure 1.1. Annual index (1978 = 100) of Fulmar apparently occupied sites in study plots at four colonies, 1976-2014 , and the mean index for the four colonies.

240 Sumburgh Head 220 Troswick Ness 200 Esha Ness 180 Burravoe, Yell 160 Mean 140

120

100

80

60 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

4 1.2b. Northern Fulmar Fulmarus glacialis: Breeding success

This was measured by counting the number of chicks present in the population plots on one date in mid August (just before the first is likely to fledge) and dividing the total by number of nest sites scored as an AOS on each of three checks in late May and early June (the photographic method, adopted in 2012), and also by the mean June count of AOS (the method used since 1985). Both methods will over-estimate the number of birds actually incubating, and marking individual sites on photographs is intended to minimise this. However, differentiating an AOS from a non-incubating adult requires judgement by the observer, and errors can be made. An AOS can also be overlooked, either through observer error or because the incubating adult is partly or wholly hidden by rocks or vegetation (large chicks are easier to detect in August because the site is surrounded by faeces and shed down). A third source of error could be that a few birds may not have laid an egg by the time of the three early visits.

A casual watch was kept on chick development at Sumburgh Head, and chicks were counted at all colonies on 13th August (Table 1.3), and scored as small (still mostly covered in down), medium (c.50% down cover) or large (little down left). There had been heavy rain overnight, with showers through the day and a Force 5 northeast wind, with many freshly moulted immature birds on the cliff (inexperienced observers could mistake these for fledged juveniles).

Table 1.3. The dates of visits to Fulmar plots in 2014, the total number nest sites scored as AOS on one or more of three checks in late May and early June, the number scored as an AOS on all three checks, the mean June count of AOS, the number of chicks present in mid August, the number of (extra) sites at which chicks were present but only qualified as an AOS on one or two of the May/June visits or were overlooked completely, breeding success ± SE calculated (a) by the marked photograph method (chicks / 3 visits + extra sites), and (b) by the population count method (chicks / mean June count), with corresponding 2013 figures in brackets.

Sumburgh Head: 30th May, 1st June, 4th June, 13th August Plot AOS 3 visits Mean Chicks Extra Success a (2013) Success b (2013) GSG 31 16 32.8 5 0 0.31 (0.63) 0.15 (0.42) GTS 175 124 159.2 77 2 0.61 (0.61) 0.48 (0.53) GPN 51 33 39.8 22 1 0.65 (0.45) 0.55 (0.45) Sum 257 173 231.8 104 3 0.59 (0.58) 0.45 (0.48) Mean 0.52 (0.56) 0.39 (0.47) ± SE 0.11 (0.06) 0.12 (0.03) th st th th Troswick Ness: 30 May, 1 June, 4 June, 13 August Plot AOS 3 visits Mean Chicks Extra Success a (2013) Success b (2013) Brei Geo 393 291 339.8 153 4 0.52 (0.57) 0.45 (0.51) Sand. Geo 534.4 229 0.43 (0.50) Sum 874.2 382 0.44 (0.50) Mean 0.44 (0.51) ± SE 0.01 (0.01) st rd th th Esha Ness: 31 May, 3 June, 6 June, 13 August Plot AOS 3 visits Mean Chicks Extra Success a (2013) Success b (2013) CG 212 135 180.8 57 8 0.40 (0.43) 0.32 (0.36) MC 33 16 30.0 9 3 0.47 (0.46) 0.30 (0.41) FG 58 37 47.2 11 3 0.28 (0.60) 0.23 (0.48) LST 6 2 4.4 2 0 1.00 (0.43) 0.45 (0.45) Sum 303 188 258.0 77 14 0.39 (0.48) 0.30 (0.40) Mean 0.38 (0.50) 0.28 (0.42) ± SE 0.06 (0.05) 0.03 (0.03) st th th th Burravoe: 1 June, 5 June, 7 June, 13 August Plot AOS 3 visits Mean Chicks Extra Success a (2013) Success b (2013) 220 144 196.4 85 12 0.54 (0.59) 0.43 (0.51)

5 At Sumburgh Head, chicks were present at three ‘extra’ sites scored as AOS on only two out of the three earlier checks. At two of these sites an adult had been present and will have been scored incorrectly, while an incubating adult had probably been overlooked at the third site. Two juveniles fully clear of down were sitting on grass slopes beside their nest sites, but it was unknown if they already had flown or not. Breeding success (by the photographic method) was higher than in 2013 at one plot, the same at another, and lower at the third and smallest plot, which is a rocky cliff facing northeast, and seems to have a high proportion of sites that are used intermittently by non-breeders (47 different sites have been marked as AOS in 2012-14).

At Troswick Ness, the single plot used for the photographic method includes all nest sites around the north, west and south sides of an east-facing geo (Brei Geo), about half of which is vertical rock cliff and half is vegetated grassy slopes with rocks. Of the four ‘extra’ sites with chicks, three were in deep holes in a grassy slope and the incubating adults will have been overlooked, while one site was scored wrongly. Many chicks were wet and bedraggled, but none were seen dead. A few chicks were completely clear of down and one was judged to have fledged from an empty site (surrounded by shed down and faeces) on a narrow ledge inaccessible to any mammalian predator.

On the first check at Esha Ness it was found that a large section of fine-meshed fishing net had been thrown into Calders Geo (CG), along with other rubbish, and was entangled halfway down the cliff, but when this disturbance had occurred was unknown. Two sites in Calders Geo with a broken egg and an unattended egg were scored as breeding AOS. The mean count of AOS at Little Stack (LST) fell below 10 in 2011, and calculated breeding success from 2011 onwards excludes this plot. Of 16 ‘extra’ sites that held chicks, eight had been overlooked on one or more of the early checks and eight had been scored wrongly. No chicks were thought to have fledged before the August check, and breeding success was markedly lower than in 2013, particularly at Fulmar Geo (FG) and in the northeast section of Calders Geo (six chicks from 44 AOS: 0.14).

The single plot at Burravoe is a large, densely occupied grassy slope and nine sites were overlooked on one or more of the June checks, while three were scored wrongly. No chicks were thought to have fledged before the August check and, as at the other three colonies, breeding success was slightly lower than in 2013.

Mean breeding success at the four colonies was 0.42 ± 0.05 (mean of June counts) and 0.49 ± 0.04 (photographic method). The trend in Fulmar breeding success in Shetland broadly follows that for Scotland as a whole (which obviously includes the Shetland data), with relatively high and stable success in the late 1980s and early 1990s (but notably poor years in 1988 and 1990), and lower and more fluctuating success since the mid 1990s, again with poor years in 2004-05 and 2007-08 (Figure 1.2; JNCC 2014).

Figure 1.2. Mean Fulmar breeding success (± SE) at 3-4 monitored colonies, 1985-2014 (Burravoe from 2003 only), calculated as the number of chicks present in mid August divided by the mean of five counts of apparently occupied sites (AOS) in June (black), and by the number of sites qualifying as AOS on each of three dates in late May and early June (red).

0.60

0.50

0.40

0.30

0.20

0.10 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

6 1.3a. European Shag Phalacrocorax aristotelis: Population counts

By late May it was apparent from breeding success plots at Sumburgh Head that there had been a reversal of the non-breeding that was prevalent in southeast Mainland in 2011-13. There had been little evidence of this in 2012 at the main colonies off southwest Mainland, where a survey of Kettla Ness, South Havra and St Ninian’s Isle on 23rd June found 148 nests (84% active), compared to 154 (74% active) in 2012, and 171 (90% active) in 2009, suggesting a slight decline in breeding numbers (Figure 1.3, Table 1.4). At Sumburgh Head, a count of 115 nests (85% active) on 9th June was 58% higher than in 2013 (73, 33% active) but 60% lower than the recent peak count of 290 nests (97% active) in 2010. There was a similar pattern of change along the coast of southeast Mainland, from Virkie north to Mousa (counted on 15-16th June): 307 nests (90% active) in 2014, 72% higher than in 2013 (178, 46% active) but 48% fewer than in 2010 (587, 97% active). The only other coast surveyed in 2014 was Papa Stour on 22nd June, and the total of 218 nests (92% active) was 27% lower than the 299 nests (93% active) counted on the most recent visit, in 2006 (Table 1.4).

Figure 1.3. Counts in June of adult Shags and nests at the main colonies around the south Mainland of Shetland. Those at Sumburgh Head were made from land, all others were from the sea. ‘Extra’ adults were those close to nest sites in addition to one adult per nest, roosting adults were on rocks away from nest sites.

Kettla Ness, South Havra, St Ninian's Isle 400

300 Roost adults

Extra adults 200 Empty/trace 100 nests Active nests 0 2009 2010 2011 2012 2013 2014

400 Sumburgh Head 300 Roost adults Extra adults 200 Empty/trace nests 100 Active nests

0 2009 2010 2011 2012 2013 2014

1200 Virkie north to Mousa 1000 Roost adults 800 Extra adults 600 Empty/trace 400 nests Active nests 200 0 2009 2010 2011 2012 2013 2014

7 Table 1.4. Counts from the sea of Shag nests (trace, empty, and active, i.e. apparently incubating or containing chicks) in June along coasts surveyed in 2011-14, the percentage of nests that were active, and count date. At No Ness and Sumburgh Head, where more than one count from land was made in a year those closest to mid June are given, except if the earlier count of active nests was higher (*).

Coastline 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Strandburgh 70 59 Ness, Fetlar 96% 68% 21/6 20/6 Lambhoga, 55 46 Fetlar 93% 78% 21/6 20/6 Southeast Yell 151 134 143 176 137 99% 95% 99% 99% 91% 21/6 29/6 16/6 22/6 19/6 Mousa 71 94 109 113 26 52 90% 89% 86% 97% 62% 94% 12/6 20/6 21/6 22/6 25/6 16/6 No Ness (land) 138* 125* 103 124 139 150 138 185* 204 134* 54 49 89 87% 78% 87% 83% 97% 95% 94% 89% 95% 84% 48% 47% 87% 28/5 27/5 15/6 14/6 13/6 22/6 13/6 23/5 9/6 27/5 12/6 10/6 12/6 No Ness (sea) 144 177 207 271 295 80 153 94% 79% 94% 97% 98% 44% 88% 12/6 20/6 4/6 21/6 22/6 25/6 16/6 Cumlewick 10 13 14 13 12 11 11 Ness 100% 77% 93% 100% 100% 64% 82% 12/6 20/6 4/6 21/6 22/6 25/6 16/6 Troswick to 175 122 114 149 165 167 61 91 Virkie 92% 89% 86% 93% 96% 96% 38% 91% 12/6 12/6 20/6 4/6 13/6 16/6 26/6 15/6 Sumburgh Head 252 221 207* 166* 233 213 215 223 290 100* 85* 73 115 (land) 97% 95% 86% 83% 97% 99% 98% 93% 97% 67% 54% 33% 85% 12/6 6/6 27/5 5/6 13/6 22/6 13/6 16/6 8/6 27/5 30/5 10/6 9/6 Roo Geo, 41 47 9 Siggar Ness 100% 96% 89% 9/6 11/6 27/6 St Ninian’s Isle 53 59 50 57 96% 93% 82% 93% 9/6 11/6 27/6 23/6 South Havra 49 57 53 46 90% 89% 58% 80% 9/6 11/6 27/6 23/6 Kettla Ness 58 51 57 51 51 45 97% 96% 89% 94% 82% 80% 6/6 16/6 9/6 11/6 27/6 23/6 West Burra 5 20 100% 100% 6/6 23/6 Skelda Ness – 219 300 210 278 291 Culs Wick 85% 96% 96% 91% 85% 11/6 27/6 21/6 9/6 20/6 Vaila 89 126 94 112 104 66% 96% 97% 97% 92% 11/6 27/6 21/6 9/6 20/6 Papa Stour 360 299 218 96% 93% 92% 13/6 28/6 22/6 Muckle Roe 76 63 62 93 67 97% 83% 89% 94% 58% 8/6 10/6 7/6 23/6 9/6

Allowing for years in there was probably a high element of non-breeding (2004-05) or that nests had been washed away by swell prior to the count (e.g. Skelda Ness to Culs Wick in 2007), the above counts and those in 1998-2001 not tabulated suggest that Shag numbers may have increased slightly along these coasts between 2002 (c. 1,900 nests) and 2010 (c. 2,100), followed by a decrease to c. 1,500 nests in 2014. However, this should not be taken as being indicative of the total Shetland population, as there were large decreases at the major colonies on Foula (from at least 2004) and Fair Isle (from 2008) during this period.

8 1.3b. European Shag Phalacrocorax aristotelis: Breeding success

This was monitored in the same 14 plots at Sumburgh Head as in 2008-13 (35 checks, 9th April to 7th October: Table 1.5). Birds were incubating at two nests on the first check, and while median date of first incubation was 20 days earlier than in 2013, this was still 20-30 days later than in the late 2000s (Figure 1.4). The number of sites with nest material (112) was 14% higher than in 2013 (98), but 56% lower than in 2010; given that a very high proportion (96%) of sites with nest material progressed to incubation in 2014, one can only assume that most of these ‘missing’ adults are now dead or have emigrated from the colony. Chicks hatched at a much higher proportion of nests than in 2011-13, and 132 were assumed to have fledged out of a minimum of 147 known to have hatched. There were no ‘swell events’ washing out nests in 2014, although some chicks probably died through chilling during bouts of heavy rain in July and early August. After three abnormal seasons, breeding success of 1.22 fledged per incubating nest was exactly the same as the average for 1988-2010 (Figure 1.5).

Figure 1.4. The estimated dates by which 25%, 50% and 75% of apparently incubating Shag nests were first recorded as such in study plots at Sumburgh Head, 1996-2014. In years when none were incubating on the first visit, the date of first recorded incubation is also shown.

100 75% 90 50%

80 25%

70 1st Inc. 60 50 40 30

Days Days from 1st April 20 10 0 2000 2002 2004 2006 2008 2010 2012 2014

Table 1.5. Shag breeding success at Sumburgh Head and Burravoe: the number of former nest sites where an adult(s) but no nest material was recorded (Ad.), the number of trace (Tr.), well-built but empty (AON), and incubated nests (Inc.), the percentage of all nests which progressed to incubation (% Inc.), the percentage of incubating nests at which chicks were recorded (% H.), the percentage of incubating nests from which no chicks fledged (Fl. 0), the number of chicks fledged (Ch.), mean brood size at fledging (Brood), and sum breeding success (Succ.: Ch./Inc.).

Sumburgh Head (14 plots) Year Ad. Tr. AON Inc. % Inc. % H. Fl. 0 Ch. Brood Succ. 2008 14 12 6 182 91.5 74.7 27.5 274 2.08 1.51 2009 13 17 4 185 89.8 76.8 28.6 250 2.05 1.58 2010 3 23 12 222 86.4 73.0 41.0 274 2.09 1.23 2011 26 21 11 141 82.1 22.5 83.0 43 1.79 0.30 2012 51 21 14 96 73.3 30.2 76.0 36 1.57 0.38 2013 36 15 27 56 57.1 16.1 83.9 15 1.67 0.27 2014 25 2 2 108 96.4 67.6 36.1 132 1.91 1.22 Burravoe, Yell (3 plots) 2012 - 6 2 36 81.8 52.8 50.0 26 1.44 0.72 2013 2 2 1 39 92.9 64.1 46.2 36 1.71 0.92 2014 6 4 2 27 81.8 81.5 25.9 42 2.10 1.56

9 Figure 1.5. Shag breeding parameters at Sumburgh Head, 1988-2014. Upper: chicks fledged per incubated nest. Lower: The percentage of: (i) nests that progressed to incubation (blue), (ii) incubating nests where chicks were known to have hatched (red), (iii) laying pairs that fledged a brood of three chicks (green).

1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

100 80 60 40 20 0 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

Shag breeding success was also monitored in the same three plots at Burravoe as in 2012-13 (31 checks, 7th April to 31st August: Table 1.5). There were 21% fewer sites with nest material than in 2013, although a high proportion (82%) again progressed to incubation, with median date of first incubation (9th May) being 11 days earlier than at Sumburgh Head. Hatching success and chick survival was high, with 42 chicks assumed to have fledged out of a minimum of 45 known to have hatched, giving a high breeding success figure of 1.56 fledged per incubating nest.

10 1.4a. Black-legged Kittiwake Rissa tridactyla: Population counts

All counts were made from the sea, by Zodiac inflatable boat. Colonies in southeast Mainland were counted on 15-16th June, and while there was little change since 2013 in the total number of nests (Table 1.6), the percentage ‘active’ in 2014 (83%) was markedly higher than in 2013 (65%); the total number of nests at these colonies was 45% lower than in 2010. The difference between the past two breeding seasons was even more apparent at colonies in the Sumburgh area (counted on 14th June), with 82% of nests active in 2014 compared to 56% in 2013; the 2014 total number of nests was 39% lower than in 2010. Colonies around southwest Mainland, between St Ninian’s Isle and West Burra, were counted on 23rd June (the Ramna Geo monitoring site at West Burra was counted from land on the same day). The total number of nests (228) was similar to that in 2012 (215), but the percentage active (72%) was higher (58%), and the 2014 nest total was 35% lower than in 2009.

Papa Stour had not been visited since 2006, and a survey on 22nd June found just 35 nests (83% active), 57% fewer than in 2006 (82, 78% active). Colonies on Foula were counted from a hard-hulled boat by Sheila Gear on 7th June, and while the total of 361 AON was slightly higher than in 2013, it was 38% lower than in 2010, very similar to the reduction in numbers over the same period around the south Mainland of Shetland.

Table 1.6. Counts of Kittiwake nests (incubating, empty and trace) and adults (excluding roosts) at breeding stations surveyed in 2014, compared with counts in 1981 (used as a baseline), and from 2005. At Foula, trace nests and adults are not counted.

SE Mainland 1981 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Mousa 148 3 nc 16 14 0 0 No Ness 1768 260 251 269 314 165 175 Troswick Ness 716 58 63 61 27 19 21 Boddam 256 43 28 35 37 20 20 The Taing, Exnaboe 0 0 0 0 0 0 1 Total nests 2888 364 342 381 392 204 217 % change p.a. -6.0 +3.7 +2.9 -19.6 +6.4 Total adults 3944 458 448 511 468 309 238

Sumburgh area 1981 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Compass Head 464 124 152 146 163 90 109 Sumburgh Head 2177 356 354 354 386 210 253 Horse Island 594 14 31 65 50+ 15 4 Total nests 3235 494 537 565 599+ 315 366 % change p.a. +4.3 +2.6 +6.0 -19.3 +16.2 Total adults 5361 617 686 896 673+ 499 460

SW Mainland 1981 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 St Ninian’s Isle 47 20 42 63 69 Ness of Ireland 203 69 41 47 42 South Havra 29 73 37 17 19 Kettla Ness 281 107 123 24 33 West Burra 615 101 110 64 65 Total nests 1175 370 353 215 228 % change p.a. Total adults 461 465 234 292

Papa Stour 1981 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Total nests 1059 82 35 % change p.a. Total adults 1948 118 50

Foula 1981 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Total AON 4978 898 1065 997 509 582 480 378 327 361 % change p.a. -4.7 +18.6 -6.4 -28.5 +14.3 -17.5 -21.3 -13.5 +10.4

11 1.4b. Black-legged Kittiwake Rissa tridactyla: Breeding success

This was monitored at the same six colonies as in 2013. Laying was again rather late, with the date by which 50% of pairs had laid remaining about two weeks later than in 1992-2001 (Table 1.7, Figure 1.6). There was less evidence of non-breeding than in recent years, although the proportion of nests that progressed to incubation was reduced by some pairs that only starting building late in the season not laying (Table 1.8).

The proportion of nests at which chicks were known to have hatched was generally quite high, with the notable exception of Ramna Geo, where after few nest failures during early incubation there was rapid onset of breeding failure in the last week of June and the first week of July. The cause of this was unknown, but must have been related to some form of disturbance or attempted predation rather than any issues with food supply, given the high hatching success and chick survival just 12 km to the south at Hich Holm. Compared with recent years, the proportion of broods of two chicks seen was quite high, although only one brood of three was recorded, at Burravoe (all three chicks fledged). Very few chicks were seen dead in the nest and chick survival was generally quite high, although the disappearance of at least 16 medium-sized chicks at Burravoe in the second half of July was also suggestive of predation rather than starvation. Despite these issues, average breeding success was the highest since 2005-06 (Figure 1.7).

There is nothing that can be done about the small sample sizes at Compass Head and No Ness, as other remaining nests at these colonies (at which breeding success may well be higher than at those monitored) are in more protected situations not visible from the cliff top.

Table 1.7. Dates by which 20%, 50% and 80% of Kittiwakes had laid at monitored colonies, 2012-2014.

Sumburgh Head Compass Head No Ness 2012 2013 2014 2012 2013 2014 2012 2013 2014 20% 27/5 1/6 26/5 29/5 31/5 30/5 29/5 31/5 31/5 50% 1/6 6/6 2/6 3/6 6/6 8/6 4/6 4/6 3/6 80% 7/6 11/6 9/6 10/6 10/6 16/6 11/6 5/6 7/6 Hich Holm, St Ninian’s Ramna Geo, Burra Burravoe, Yell 2013 2014 2012 2013 2014 2012 2013 2014 20% 3/6 28/5 1/6 6/6 30/5 29/5 27/5 29/5 50% 7/6 4/6 9/6 10/6 5/6 2/6 3/6 2/6 80% 14/6 10/6 13/6 15/6 10/6 12/6 8/6 9/6

Figure 1.6. Dates by which 50% of Kittiwakes breeding that year were presumed to have laid their first eggs at colonies that have been monitored by SOTEAG, 1989-2014.

45

40

35

30

25

20

15 Days fromMayDays 1st 10 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 Burravoe, Yell Esha Ness Clett Head, Whalsay Westerwick Ramna Geo, Burra Kettla Ness St Ninian's isle No Ness Troswick Ness Compass Head Sumburgh Head

12 Table 1.8. The number of Kittiwake nests and occupied sites at monitored colonies 2005-2014; the percentage of: (i) all nests at which incubation was recorded or assumed, (ii) incubating nests in which at least one chick was known to have hatched, (iii) hatched nests in which two chicks were seen, (iv) nests where young hatched in which one or more dead chicks were seen, (v) incubating nests that failed; the number of young fledged; breeding success (young fledged per incubating nest). Mean and standard error are also given for plots at Sumburgh Head; all visible nests are monitored at the other colonies.

Sumburgh Head 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Total nests 128 156 163 148 177 177 145 139 138 150 Incubating 111 144 128 89 128 151 94 93 89 115 % Incubating 86.7 92.3 78.0 60.1 72.3 85.3 64.8 66.9 64.5 76.7 Sites adult(s) only 20 4 20 36 39 22 39 35 40 29 % Nests hatched 90.1 89.6 82.8 21.3 80.5 86.8 21.3 60.2 32.6 85.2 % Nests hatched b/2 45.0 34.1 17.9 5.3 24.3 11.5 15.0 1.8 0 46.9 % Hatched with dead 2.0 8.5 12.3 5.3 3.9 8.4 10.0 26.8 20.7 2.0 % Nests failed 14.4 26.4 46.9 98.9 44.5 88.1 100 84.9 100 20.9 Chicks fledged 129 125 69 1 75 18 0 14 0 132 Sum success 1.16 0.87 0.54 0.01 0.59 0.12 0 0.15 0 1.15 Mean success 1.21 0.70 0.47 0.51 0.11 0 0.13 0 1.20 SE 0.07 0.14 0.08 0.09 0.06 0.04 0.10

Compass Head 2008 2009 2010 2011 2012 2013 2014 Total nests 61 62 55 21 24 21 23 Incubating 37 41 41 10 18 13 15 % Incubating 60.7 66.1 74.5 47.6 75.0 61.9 65.2 Sites adult(s) only 3 5 2 6 8 5 2 % Nests hatched 13.5 65.9 73.2 30.0 38.9 30.8 60.0 % Nests hatched b/2 0 17.9 13.3 0 14.3 0 55.5 % Hatched with dead 0 14.3 53.3 0 0 50.0 0 % Nests failed 100 56.1 100 100 88.9 100 40.0 Chicks fledged 0 19 0 0 3 1 14 Sum success 0 0.46 0 0 0.17 0.08 0.93

No Ness 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Total nests 28 30 31 43 45 50 29 22 19 17 Incubating 23 26 23 32 39 38 21 16 14 14 % Incubating 82.1 86.7 74.2 74.4 86.7 76.0 72.4 72.7 73.7 82.4 Sites adult(s) only 7 4 2 14 0 0 8 9 5 4 % Nests hatched 87.0 84.6 87.0 40.6 74.4 50.0 38.1 31.3 0 71.4 % Nests hatched b/2 25.0 27.3 10.0 0 34.5 15.8 0 0 0 60.0 % Hatched with dead 10.0 13.6 15.0 7.7 6.9 5.3 0 20.0 0 0 % Nests failed 21.7 26.9 82.6 75.0 51.3 100 100 100 100 35.7 Chicks fledged 19 20 4 8 23 0 0 0 0 15 Sum success 0.83 0.77 0.17 0.25 0.56 0 0 0 0 1.07

Hich Holm 2013 2014 Total nests 58 61 Incubating 38 54 % Incubating 67.9 88.5 Sites adult(s) only 5 6 % Nests hatched 13.2 77.8 % Hatched b/2 0 61.9 % Hatched with dead 0 0 % Nests failed 100 27.8 Chicks fledged 0 64 Sum success 0 1.19

13 Table 1.8. continued.

Ramna Geo, Burra 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Total nests 98 110 124 91 111 117 76 64 48 68 Incubating 82 101 100 55 81 74 45 24 34 64 % Incubating 83.7 91.8 80.6 60.4 73.0 63.2 59.2 37.5 70.8 94.1 Sites adult(s) only 8 7 6 16 14 11 22 15 8 13 % Nests hatched 65.9 84.2 80.0 16.9 85.2 18.9 2.2 0 35.3 6.2 % Hatched with b/2 25.9 22.4 30.0 10.0 62.3 7.1 0 0 0 0 % Hatched with dead 1.9 1.2 7.5 0 0 14.3 0 0 8.3 0 % Nests failed 36.6 22.5 30.0 83.1 17.3 98.6 100 100 70.6 100 Chicks fledged 62 94 80 11 103 1 0 0 10 0 Sum success 0.76 0.92 0.80 0.19 1.27 0.01 0 0 0.29 0

Burravoe, Yell 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Total nests 73 89 104 98 113 135 117 128 130 114 Incubating 66 80 94 85 99 107 87 94 99 95 % Incubating 90.4 89.9 91.0 86.7 87.6 79.3 74.4 73.4 76.2 83.3 Sites adult(s) only) 2 1 1 7 4 8 12 9 15 16 % Nests hatched 78.8 85.0 87.2 34.1 72.7 69.2 28.7 51.1 40.4 76.8 % Hatched with b/2 36.5 30.9 25.6 34.5 51.5 6.8 8.0 43.8 2.5 60.3 % Hatched with dead 0 2.9 4.9 0 1.4 8.1 4.0 2.1 15.0 1.4 % Nests failed 21.2 25.0 26.6 72.9 35.4 53.3 78.2 59.6 87.9 32.6 Chicks fledged 70 76 81 33 95 52 20 49 12 100 Sum success 1.06 0.95 0.86 0.39 0.96 0.49 0.23 0.52 0.12 1.05

Figure 1.7. Mean Kittiwake breeding success (+ SE) at colonies (4-7 per year) monitored by SOTEAG, 1986-2014. 1.25

1.00

0.75

0.50

0.25

0.00 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

One unusual feature of the post-breeding season noted at Sumburgh Head was that adults and a few fledged young attended the colony well into October, long after the last chicks had fledged. Adults were flying in and out of the nesting geos, calling excitedly, and certainly appeared to be in healthy condition.

14 1.5a. Common Guillemot Uria aalge: Population counts

The number of adult Common Guillemots in study plots was higher than in 2013 at all four monitored colonies (Table 1.9). This, however, almost certainly reflected a return to a more ‘normal’ breeding season after low and erratic colony attendance in 2013, rather than any increase in the population of adults of breeding age. These counts suggest that this population has been in slight, gradual decline over the past decade, after a more sudden decrease in the early 2000s (Figure 1.8). The mean population index (1978 = 100) at these four colonies averaged 47.1 during 2005-14, compared to 80.3 during 1992-2001.

At Esha Ness and Burravoe, all Common Guillemots are included in the plot counts, whereas at Troswick Ness all breeding ledges visible from the cliff top are included (c.50% of the colony can only be seen from the sea). At Sumburgh Head, very few Common Guillemot ledges are not visible from the cliff top, but the eight monitoring plots comprise only 10-12% of the colony. A whole-colony count of 7,441 birds was made on 9th June, a warm, sunny day with light winds, and when the plot count total was only 2.5% higher than the mean given in Table 1.9. Since 2007, these annual whole-colony counts have more or less tracked annual changes in numbers in the plots (Figure 1.9, Table 1.10). However, allowing for low colony attendance in 2011 and 2013, the latter now seem to be declining whereas the whole colony counts may be more stable.

Table 1.9. Mean counts of individual Common Guillemots in study plots at four Shetland colonies, 2013 and 2014. Statistics are: number of counts, range, mean, standard deviation, coefficient of variation, percentage change since 2013, and population indices (1978 = 100).

Colony Unit Year n Range Mean SD CV % ch. Index Sumburgh Birds 2013 5 376-749 610.6 141.84 0.23 46.0 Head 2014 5 758-901 838.4 52.47 0.06 +37.3 63.2

Troswick Birds 2013 5 194-226 217.0 14.27 0.07 39.5 Ness 2014 5 246-287 264.2 15.27 0.06 +21.8 48.1

Esha Ness Birds 2013 5 2-23 10.4 8.17 0.79 1.5 2014 5 8-48 27.4 14.36 0.52 +163.5 3.9

Burravoe Birds 2013 5 110-175 139.6 25.45 0.18 41.8 2014 5 183-225 202.8 15.97 0.08 +45.3 60.7

Figure 1.8. Annual index (1978 = 100) of Common Guillemot numbers in study plots at four monitored colonies, 1976-2014, and the mean index for the four colonies.

175

150

125

100

75 Sumburgh 50 Troswick Eshaness 25 Burravoe Mean 0 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

15 Figure 1.9. Comparison of trends in census counts of the Sumburgh Head Common Guillemot colony on a single date in June, and the mean of the total of five counts in eight study plots.

18000 2500 16000 2250 14000 2000

1750 12000 1500 10000 1250 8000 1000 6000 750 Total Colony Counts 4000 500 2000 Total Plot Counts 250 TotalPlot Counts

Total Colony TotalColony Counts 0 0

Table 1.10. Year-to-year changes in Common Guillemot numbers at Sumburgh Head, as recorded by the mean of five counts in study plots, and a single count of the entire colony.

Years Plot counts Colony count Difference 2007-08 -11.0% +2.5% 13.5% 2008-09 +12.2% +8.3% 3.9% 2009-10 -6.7% -10.4% 3.7% 2010-11 -17.6% -30.2% 12.6% 2011-12 +10.8% +47.3% 36.5% 2012-13 -24.8% -14.1% 10.7% 2013-14 +37.3% +18.5% 18.8%

16 1.5b. Common Guillemot Uria aalge: Breeding success and chick diet at Sumburgh Head

This was again monitored in a single plot on the east side of the Head, which was checked daily from 7th April until 2nd August (except 19th June), with the number of adults present at the start of the check being recorded. The normal pre-laying cyclical pattern of attendance occurred, with 1st May being the last day no birds were present in the plot (or anywhere else on the Head) before laying (Figure 1.10).

The first egg was seen on 6th May, at the same site as the first egg in 2013, but it was broken by the following afternoon. The next eggs (4) were seen on 9th May and thereafter laying was rapid with a median laying date of 16th May (Table 1.11). The first display fish seen was a medium-sized sandeel on 11th May. In contrast to 2013, when it was believed many off-duty mates were foraging far from the colony for days on end, observations of mixed bridled:non-bridled pairs indicated frequent change-overs during incubation, and only one egg was seen apparently abandoned, on 18th May four days after laying; both mates were present the next day and the chick hatched after 37 days incubation. Spells of heavy rain caused few problems during incubation, and a small spike in egg loss was due to some severe and prolonged fighting that erupted suddenly on 26th May. The last two apparent first eggs (5th and 13th June) may have been relays after the quick loss of first eggs, but no pair that lost an egg after 5th June relaid.

Table 1.11. Common Guillemot breeding parameters and success in a study plot at Sumburgh Head, 2004- 2014, calculated as young fledged (a) per regularly attended site and (b) per site at which eggs were laid.

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Attended sites 144 162 163 165 166 169 169 164 163 155 158 Sites with egg laid 108 117 136 142 137 144 154 142 140 98 122 % sites laid 75% 72% 83% 86% 83% 85% 91% 87% 86% 63% 77% First egg date 13/5 11/5 8/5 4/5 4/5 2/5 2/5 29/4 4/5 7/5 6/5 Median laying date 23/5 26/5 19/5 11/5 16/5 10/5 9/5 9/5 14/5 19/5 16/5 % Hatched first egg 31% 50% 62% 66% 49% 65% 68% 21% 68% 11% 66% Chicks fledged 9 66 78 80 39 91 78 2 55 0 66 Fledged/site 0.06 0.41 0.48 0.48 0.23 0.54 0.46 0.01 0.34 0.00 0.42 Fledged/egg 0.08 0.56 0.57 0.56 0.28 0.63 0.51 0.01 0.39 0.00 0.54

The first (2) chicks were seen on 11th June. Hatching success of first eggs was 66% (81/122), a marked improvement on 2013 (Table 1.11), while 50% of the 16 relay eggs hatched. Parental attendance was very high, and although some chicks wandered off-site and were temporarily brooded and even fed by neighbours, no chick was ever recorded as unattended, with neither parent apparently on site. Chick survival was also aided by an influx of apparent non-breeders in mid June, which persisted for four weeks and helped protect against predatory gulls. Despite this, one Great Black-backed Gull took to standing motionless for long periods on the edge of the breeding group, then suddenly lunging in and taking a chick; this gull was almost certainly responsible for at least eight of the 19 first-egg chicks lost (Table 1.12).

A 17-day old chick missing on the morning of 30th June was the first to possibly have fledged; although the next fledging was not until the night of 5/6th July (five chicks aged 22-25 days), this initial chick was well- developed and had been well protected, in the centre of a dense cluster of sites. The last first-egg chicks fledged on the night of 19-20th July, by which time there were still one first egg (infertile), three relay eggs (one infertile, two hatched) and five relay chicks in the plot, with 152 adults present. The number of adults then dropped rapidly, to 40 on 24th July and eight on 27th July, and only three of these seven relay chicks survived to possible fledging, the last on 1-2nd August aged 18 days. Overall success was 0.54 chicks fledged per breeding pair.

The following three first-egg chicks went missing aged 15-19 days, but were judged not to have fledged, and including these in the fledged total would have raised success to 0.57 per breeding pair: missing at 0900 on 27th June aged 15 days, sea was very rough overnight with a strong northeast wind, no others fledged yet; missing at 0900 on 3rd July aged 17 days, very heavy swell overnight, all other chicks present, site next to where the Great Black-backed Gull had been taking chicks; went missing between 1200-1600 on 9th July aged 19 days, parent on site looking agitated, daytime fledging has never been seen at the plot.

17 Figure 1.10. Upper: The daily number of adults, first eggs, relay eggs, first egg chicks, and relay egg chicks in the breeding success plot at Sumburgh Head in 2014, and the cumulative number of fledged first-egg chicks and relay-egg chicks. Lower: The number of eggs and chicks missing from the previous day, or known to have been lost that day.

225 200 Adults 175 150 125 100 75 50 25 0 01-May 11-May 21-May 31-May 10-Jun 20-Jun 30-Jun 10-Jul 20-Jul 30-Jul

125

100 Relay egg 75 First egg 50 25 0 01-May 11-May 21-May 31-May 10-Jun 20-Jun 30-Jun 10-Jul 20-Jul 30-Jul

100 75 Relay egg chick 50 First egg chick 25 0 01-May 11-May 21-May 31-May 10-Jun 20-Jun 30-Jun 10-Jul 20-Jul 30-Jul

100 75 Cumulative relay egg chick fledged 50 Cumulative first egg chick fledged 25 0 01-May 11-May 21-May 31-May 10-Jun 20-Jun 30-Jun 10-Jul 20-Jul 30-Jul

8 Lost relay egg chick 6 Lost first egg chick 4 Lost relay egg Lost first egg 2 0 01-May 11-May 21-May 31-May 10-Jun 20-Jun 30-Jun 10-Jul 20-Jul 30-Jul

18 Table 1.12. Causes (%) of breeding failure of Common Guillemots at Sumburgh Head, 2009-14.

2009 2010 2011 2012 2013 2014 Number of failed breeding attempts 53 76 140 85 98 56 Lost first egg before possible hatching (< 29 days), no relay 35.8 19.7 31.4 24.7 50.0 25.0 Lost first egg around possible hatching (29-37 days), no relay 7.5 3.9 6.4 4.7 4.1 16.1 Presumed infertile first egg, incubated 38+ days 11.3 13.3 0.7 1.2 0 5.4 Lost relay egg before possible hatching (< 29 days) 20.8 11.8 25.7 11.8 34.7 10.7 Lost relay egg around possible hatching (29-37 days) 0 3.9 5.0 3.5 0 1.8 Presumed infertile relay egg, incubated 38+ days 0 0 0.7 1.2 0 1.8 Lost first egg chick before presumed fledging 17.0 36.8 20.0 50.6 11.2 32.1 Lost relay chick before presumed fledging 7.5 10.5 10.0 2.4 0 7.1

Since 2000, adult Common Guillemots in the breeding success plot have been counted at a set time on the same afternoons as the population counts, giving a measure of colony attendance per regularly attended site and per breeding pair during the season, and per incubating or brooding adult on the day (Table 1.13). In 2014, colony attendance (per breeding pair) was the highest since 2005 (Figure 1.11), and indeed would have been even higher had the counts been made in late June when the number adults present at the time of the check (not corrected for time of day or weather conditions) averaged 192 (Figure 1.10), equivalent to a k-value (b/n) of 0.64 (Table 1.13).

Table 1.13. Details of counts of Common Guillemots in the Sumburgh Head breeding success plot in 2014 (with mean and standard deviation), breeding numbers, derived k values (with mean and standard deviation), and the deviation of counts in population monitoring plots on the same dates from the monthly mean.

Count date in 2014 31/5 5/6 7/6 9/6 13/6 Mean SD Time (BST) 1310 1310 1310 1310 1310 Total birds in plot (n) 155 164 148 166 168 160.2 8.44 Total regularly attended sites (a) 158 158 158 158 158 Total breeding pairs (b) 122 122 122 122 122 No. of eggs or chicks on count date (c) 101 105 103 102 99 k-value regular sites (a/n) 1.02 0.96 1.07 0.95 0.94 0.99 0.06 k-value breeding pairs (b/n) 0.79 0.74 0.82 0.73 0.73 0.76 0.04 k-value eggs and chicks (c/n) 0.65 0.64 0.70 0.61 0.59 0.64 0.04 Population count as % of mean for 2014 90% 101% 99% 103% 108%

Figure 1.11. The Sumburgh Head Common Guillemot population index (black, 1978 = 100), and the mean number of adults present in the breeding success plot per 100 regularly attended sites (blue) and per 100 breeding pairs (red) on the dates and times of the population counts, 2000-2014.

175

150

125

100 Ratios 75

Index (1978 = 100) / / 100) = (1978Index 50

25 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

19 Chick feeding watches were carried out in the area of the Sumburgh Head breeding success plot on 12 days in late June and early July, and included many pairs with chicks outside the plot so as to maximise the number of confirmed chick feeds rather than obtain feeding rates of individual chicks. Of 629 feeds, 614 fish were identified to type based previous experience and use of a field guide to sea fishes (Table 1.14). Sandeels comprised 25.3% of feeds, and while most were similar to those in previous years (presumably Ammodytes marinus) some appeared to be of a different species, being less shiny and a different colour. The proportion of sandeels ranged from 51% on 21st June (43 feeds) to 11% on 28th June (57 feeds), highlighting the need for a large number of observations spread throughout chick-rearing (Figure 1.12). Gadids dominated the chick diet (69.8%), and most appeared to be small to medium Saithe Pollachius virens, while 2.5% were clupeids and 2.4% could not be identified to any type, either because the feed was too quick or the item was too small to see properly.

Many fish (especially Saithe) were wet and a few were still alive when delivered so had clearly been caught close to the colony. Since the chicks observed included those in the success plot which were individually known, some observations on minimum feeding frequency could be made (Table 1.15). Food seemed particularly abundant on 5-7th July, when some adults brooding chicks had undelivered chicks in their bills and some chicks were seen to refuse feeds, including one 16-day chick that was brought at least four Saithe in 55 minutes on 6th July, refusing to eat the last.

Table 1.14. The proportions of fish types (n = 629) fed to Common Guillemot chicks at Sumburgh Head on 12 2-hour feeding watches, 17th June to 8th July. ‘Rockling-type gadid’ includes what appeared to be small indeterminate gadids based on colour and tail shape, as well as several obvious Three-bearded Rockling.

Fish type Small Medium Large Total Sandeel 9.2 (58) 9.1 (57) 7.0 (44) 25.3 (159) ‘Saithe-type’ gadid 29.1 (183) 24.3 (153) 1.3 (8) 54.7 (344) ‘Whiting-type’ gadid 0.6 (4) 1.6 (10) 3.5 (22) 5.7 (36) ‘Rockling-type’ gadid 8.9 (56) 0.5 (3) 0.0 (0) 9.4 (59) Clupeid 1.6 (10) 0.6 (4) 0.3 (2) 2.5 (16) Unidentified but not sandeel 2.2 (14) 0.2 (1) 0.0 (0) 2.4 (15)

Figure 1.12. The proportion of prey items of different fish families fed to Common Guillemot chicks on 12 dates in 2014, and the total (n = 629). 100%

80%

60% % Unident. 40% % Clupeid

20% % Gadid % Sandeel

0%

06-Jul 01-Jul 02-Jul 03-Jul 04-Jul 05-Jul 07-Jul 08-Jul

23-Jun 17-Jun 18-Jun 19-Jun 20-Jun 21-Jun 22-Jun 24-Jun 25-Jun 26-Jun 27-Jun 28-Jun 29-Jun 30-Jun TOTAL

Wing lengths and weights were taken of 33 chicks during ringing at nearby Compass Head on 1st July, but the chicks were too small (maximum wing length was 52 mm) for the data to be used as indicative of fledging weight.

20 Table 1.15. Instances of Common Guillemot chick feeds 30 minutes or less apart (bold). These are minima, as chicks may have received additional feeds un-noticed.

Date Chick (age) Feeds (time and fish type) 17/6 36B (5d) 1337 large whiting; 1446 small saithe; 1459 small sandeel; 1515 small saithe 20/6 36C (5d) 1553 small saithe; 1621 medium saithe; 1648 medium saithe; 1718 small saithe 21/6 78B (2-3d) 1127 medium saithe; 1145 medium saithe 24/6 9A (11d) 0925 small orange rockling; 0941 small u/d gadid; 1004 small u/d gadid 25/6 45 (1d) 1457 medium sandeel; 1505 medium sandeel 25/6 87 (14d) 1535 small saithe; 1557 small saithe 27/6 10 (8-9d) 1300 small orange rockling; 1402 small orange rockling; 1419 small rockling 27/6 78A (8-9d) 1305 small whiting; 1333 small clupeid 27/6 3 (12d) 1326 small saithe; 1337 medium saithe 27/6 43 (7d) 1415 large whiting; 1425 large whiting 3/7 35 (23d) 1044 small saithe; 1053 small saithe; 1120 medium saithe 5/7 37 (10d) 0914 small saithe; 0944 medium saithe 6/7 43 (16d) 1019 small saithe; 1030 small saithe; 1042 small saithe; 1114 medium saithe 6/7 27 (11d) 1107 large sandeel; 1120 medium saithe 7/7 68A (16d) 0932 medium saithe; 1000 medium saithe 7/7 44 (18-19d) 1014 small clupeid; 1046 small saithe; 1113 small saithe 7/7 16 (10d) 1041 medium saithe; 1058 small saithe

21 1.5c. Common Guillemot Uria aalge: Breeding success at Burravoe, Yell

This was monitored in the same plot as in 2012-13 (Table 1.16). Because viewing distances from three safe vantage points are greater than at Sumburgh Head, the presence of an egg is more difficult to confirm, and sites at which eggs were assumed to have been laid were defined as those where an adult was sitting tight (ST) throughout the visit on two consecutive dates. Other sites where an adult was sitting tight on one or more non-consecutive dates from the date of first assumed laying to 30th June (Table 1.14, b), or where adults were only ever recorded as standing upright on two or more dates (Table 1.14, c) are listed separately. An incubation period of 32 days and a minimum fledging period of 15 days were used to calculate breeding success, while the state of plumage development of chicks that were seen well was also used as a guide to ascertain their probable age.

Two eggs were seen and another bird was sitting tight on the first check, on 12th May. Given the infrequency of checks and the difficulty of confirming actual incubation and hatching, one cannot be too precise about phenology but laying was undoubtedly later than in the Sumburgh Head success plot, and 47% of chicks known to have hatched were still present on 16th July, whereas only 12% of first-egg chicks and all six relay- egg chicks (two had still to hatch) remained at Sumburgh on that date.

There was much fighting on 22nd May, when two rolled eggs were seen, and fighting again between non- breeders on 7th July. As at Sumburgh Head, there appeared to be a small influx of non-breeders from mid June to mid July; the mean count of adults on seven checks from 29th May to 17the June was 150, and 168 on seven checks from 20th June to 10th July.

Chicks were known to have hatched at 63% of assumed breeding sites, very similar to first-egg hatching success at Sumburgh Head, but only two chicks (4%) were judged to have been lost. This may be over- optimistic, but predation by gulls or Great Skuas does not appear to be a problem for Guillemots at Burravoe whereas these birds patrol Sumburgh throughout chick-rearing. Two large chicks, at least 20 days old, were still present on 1st August and were assumed to have fledged as the colony was deserted on 6th August. Breeding success at 0.61 per pair assumed to have laid was markedly higher than in 2013, and slightly higher than in 2012.

The first display fish seen were two large sandeels on 5th June. No feeding watches were carried out, but of 34 chick feeds noted between 20th June and 28th July, 16 (47%) were sandeels (3 large, 12 medium, 1 small), 13 (38%) were gadids (3 large, 10 medium), all thought to be Saithe, one (3%) was a medium clupeid, and four (12%) were unidentified.

Table 1.16. Details of Common Guillemot breeding success monitoring at Burravoe in 2012-14. Adults sitting tight (ST) on two or more consecutive checks were assumed to be incubating. Those sitting tight on just one, or on two or more non-consecutive checks were assumed not to have laid an egg, although a second measure of breeding success includes these sites.

2012 2013 2014 Date range visited 8/5 – 27/7 2/5 – 8/8 12/5 – 6/8 Checks (mean interval in days) 26 (3.2 d) 30 (3.4 d) 27 (3.2 d) Date first egg seen / assumed incubation 8/5 16/5 12/5 ST 2+ checks, assumed laid (a) 115 75 90 ST 1 check only from first egg to 30/6 (b) 11 17 19 Other regularly attended sites (c) 3 38 34 % laid (a/a+b+c) 89.1% 57.7% 62.9% Sites where chicks were seen 62 30 57 Minimum % hatched 53.9% 40.0% 63.3% Date first assumed fledged 30/6 – 2/7 8 - 11/7 30/6 – 3/7 Number assumed fledged (d) 59 27 55 Success (d/a) 0.51 0.36 0.61 Success (d/a+b) 0.47 0.29 0.50

22 1.6a. Razorbill Alca torda: Population counts

As with Common Guillemot, numbers in study plots were uniformly higher than in 2013, although sample sizes are now very small except at Sumburgh Head (Table 1.17). The first count at Sumburgh Head (63 on 31st May) was the lowest and the last count (120 on 13th June) was the highest, the other three ranging from only 81-98. A whole-colony count at Sumburgh Head on 9th June was 20% higher than in 2013 (Table 1.18), very similar to the increase recorded in the study plots.

Table 1.17. Mean counts of individual Razorbills in study plots at four Shetland colonies, 2013 and 2014. Statistics given are: number of counts, range, mean, standard deviation, coefficient of variation, percentage change since 2013, and population indices (1978 = 100).

Colony Unit Year n Range Mean SD CV % ch. Index Sumburgh Birds 2013 5 50-87 76.6 15.37 0.20 26.5 Head 2014 5 63-120 91.0 21.08 0.23 +18.8 31.4

Troswick Birds 2013 5 1-4 2.2 1.10 0.50 10.5 Ness 2014 5 4-8 6.2 1.79 0.29 +181.8 29.5

Esha Ness Birds 2013 5 1-9 4.8 2.86 0.60 6.6 2014 5 4-11 7.2 2.86 0.40 +50.0 9.9

Burravoe Birds 2013 5 6-9 7.8 1.30 0.17 65.0 2014 5 8-11 10.2 1.30 0.13 +30.8 85.0

Figure 1.13. Annual index (1978 = 100) of Razorbill numbers at Sumburgh Head and Esha Ness, 1976- 2014, and the mean of indices at these two colonies plus Troswick Ness and Burravoe.

120.0

100.0

80.0

60.0

Sumburgh Head 40.0 Esha Ness 20.0 Mean of 4 colonies 0.0 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

Table 1.18. Whole colony counts from land of Razorbills at Sumburgh Head. In 2007, an additional 32 birds were counted from the sea on 7th June in areas judged to be not visible from the cliff top.

2001 6/6/07 18/6/08 16/6/09 8/6/10 19/6/11 11/6/12 10/6/13 9/6/14 626 199 197 192 133 204 189 151 181

23 1.6b. Razorbill Alca torda: Breeding success at Sumburgh Head

This was monitored for the fourth successive year, using the same marked photographs from previous years and adding on any new nest sites as they became apparent. The presence and number of attending adults at potential nest sites was recorded and pairs were assumed to have laid an egg if an adult was recorded as sitting tight (ST) on two or more consecutive checks (Table 1.19). An incubation period of 35 days, a minimum fledgling period of 15 days, and the state of chick plumage development were all used to help assess probable hatching periods, chick ages, and whether they could have fledged or not. The nest sites monitored were scattered around six areas of the Head where Razorbills could be seen reasonably closely using a telescope at a safe vantage point, and it would be spurious to clump them into ‘plots’.

Timing of laying was evidently earlier than in the Guillemot breeding success plot, as pairs were assumed to have laid at 20 sites (eggs seen at 10) on the first check on 7th May. Viewing distance and angle affected the chance of an egg being seen, and no egg was seen at 35 (60%) of the 58 sites assumed to have laid. Chicks were known to have hatched at 32 sites (55%) and of these, 30 were assumed to have fledged, the first between 21-25th June, and the last by 26th July. Success was therefore calculated as 0.52 fledged per assumed breeding pair, more than twice as high as in 2013 and similar to that in 2012. The only clue as to causes of failed breeding attempts was that on 23rd May two sites were noted as having been flooded by heavy rain. The only chick feed noted was on 21st June, a beak full of apparently 0-group sandeels.

Table 1.19. The number, status and outcome of Razorbill breeding sites monitored at Sumburgh Head, 2011-14. Adults sitting tight (ST) on two or more consecutive checks were assumed to be incubating. Those sitting tight on just one, or on two or more non-consecutive checks were assumed not to have laid an egg, although a second measure of breeding success includes these sites.

2011 2012 2013 2014 Date range visited 4/5–11/7 3/5–26/7 3/5–6/8 7/5-26/7 Checks (mean interval in days) 22 (3.2 d) 42 (2.0 d) 41 (2.4 d) 26 (3.1 d) First egg seen / assumed incubation 4/5 3/5 8/5 7/5 ST 2+ checks, no egg seen (a) 15 25 25 35 Egg seen (b) 32 29 18 23 Breeding pairs (a + b) 47 54 43 58 ST 1 check only from first egg to 30/6 (c) 10 5 15 10 Other attended sites 6 7 14 19 Sites where chicks were seen 7 38 13 32 Date first assumed fledged None 27-28/6 16/7 21-25/6 Chicks assumed to have fledged (d) 0 30 10 30 Success (d/a+b) 0.00 0.56 0.23 0.52 Success (d/a+b+c) 0.00 0.51 0.17 0.44

24 2. Pre-breeding counts of Black Guillemots Cepphus grylle

Monitoring logistics and constraints Counts are only attempted in conditions of little onshore swell, little or no wind or (at most) a light to moderate offshore breeze, and no precipitation. Ideally two counts of each section are made each year, but this is not always possible. Birds ashore are flushed onto the sea where they join displaying groups and can be readily counted, but their willingness to leave cliff perches varies from day to day, and diminishes by early May, when fieldwork stops. After 09.00 BST birds tend to disperse to feed, but the timing of this varies, with birds occasionally departing the colony area unusually early. Some counts are therefore ‘better’ than others, either because of sea conditions or the birds’ behaviour, and priority for second counts is given to coastal stretches where the first count was suspected to have been low for those reasons.

The 2014 counts No count was made at Ronas Voe this year, while the single count made in good conditions at Hillswick Ness (2nd May) was slightly higher than in 2013 (Table 2.1; Figure 2.1).

Table 2.1. Pre-breeding counts of adult Black Guillemots at colonies, 2005-14. Counts in brackets were the only ones made that year, those not in brackets were the higher of two. Counts in bold were made in favourable conditions, those not in bold may have been low (*or definitely were low) because of adverse conditions, or because birds were difficult to flush from cliff perches. Percentage change is from 2013, or 2012 if indicated**.

West Coast 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 % change Ronas Voe [101] 114 [117] [112] 101 [137] 131 80 [101] Hillswick Ness 214 [238] [233] 266 [286] [293] [249*] [284] [260] [276] +6.2 % Mu Ness-Wats Ness [276] [261] [273] 292 [336] [264*] [351] [285*] [286] -18.5 %** West Burra [221] [230] 204 233 270 [258] [279] 244 [228] -6.6 % West Total 812 843 827 903 993 902* 994 890*

East Coast 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 % change Lunning 68 57 63 [64] [67] 72 84 [68] [88] [64] -27.3 % Levaneap 240 241 [224] [271] 268 270 [271] 246 [218] -11.4 % Kirkabister 132 148 140 [164] [170] 169 181 174 179 [151] -15.6 % Aithsetter [86] 93 99 [95] [100] 112 125 114 116 112 - 3.4 % Mousa [108] [115] [99] 137 [158] [194] 182 [176] [154] -12.5 %** Boddam-Virkie [102] 116 117 [121] [120] 136 132 [131] 115 -12.2 % East Total 736 770 755 887 935 978 935 814 -12.9 %

Overall Total 1548 1613 1582 1880 1880* 1929

Figure 2.1. Counts of adult Black Guillemots in northwest Mainland, at Hillswick Ness (black) and Ronas Voe (blue), 1983-2014. Open symbols indicate the lower count when two were made in a year.

300

250

200

150

100

50

0 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

25 Wats Ness to Dale and Mu Ness are separated by the Voe of Dale, and it is difficult for one observer to cover this coast thoroughly in a single morning before birds begin to disperse from their colonies. On 28th April MH walked north from Wats Ness while MM started at Mu Ness and walked south, meeting at the Ness of Bakka after 90 minutes. Sea and light conditions were perfect, birds flushed easily from cliff perches, and numbers were genuinely lower than the count on 22nd April 2012 (Figure 2.2; the 2011 and 2013 counts were low because of difficult sea conditions and the birds’ behaviour and are not plotted). Although using up two man-mornings, this is the most accurate way to cover this coast, which has some large colonies, as it allows time for repeated counts of birds on the water; of the counts tabulated, those in 2006 and 2012 were also made by two observers in the same time-frame (Table 2.1). Counts for the two sections have been previously been presented separately, but given that displaying groups on either side of the Voe of Dale are only 500 m apart, it is probably best to regard Mu Ness to Wats Ness as a single section.

West Burra and Kettla Ness, separated by the small bay of Banna Minn, are also contiguous and normally covered by two observers in a single morning, one walking north and one south from Banna Minn; as the closest displaying groups are only 400 m apart counts are now presented as one section (Figure 2.2). Although only one count was made (27th April), conditions were good and birds behaved well, and as in 2013, numbers were believed to be genuinely lower than in 2012. A few nest sites were probably lost in a rock fall in winter 2012/13, but this would only account for 5-6 birds out of a deficit of c.50 since 2012.

Figure 2.2. Counts of adult Black Guillemots at Wats Ness to Mu Ness, west Mainland (black) and West Burra, southwest Shetland (blue), 1983-2014. Open symbols indicate the lower count when two were made in a year. Black symbols overlap in 2008, blue symbols overlap in 1999, 2007, 2008 and 2009.

400

350

300

250

200

150

100 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

In northeast Mainland, a single count at Lunning (15th April) in good to moderate conditions was 27% lower than in 2013, although the sample size is small on this section and the difference only involved 24 birds (Table 2.1). This is a difficult section to survey from land as many cliff-faces cannot be seen safely and overlooking a few birds sitting quietly at nest sites can result in a relatively large proportional change. The single count at Levaneap (2nd May) was in good conditions, birds flushed easily and stayed close inshore displaying. The count was 26-28 birds lower than the two counts in 2013, and most of this difference was at one discrete and easily counted geo where there had been a large rock fall (count of 24 adults c.f. 47 and 49 in 2013). The single count at Kirkabister (18th April), also in good conditions, was 28 birds lower than two counts of 179 in 2013; most birds were already on the sea and the few ashore flushed easily.

In southeast Shetland, the higher of two counts in 2013 (116) and 2014 (112) at Aithsetter were very similar; sea conditions and the birds’ behaviour were favourable on both dates. Birds were difficult to flush on the first count (103, 9th April) at Boddam to Virkie, but were more co-operative on 18th April, when the total was 16 birds lower than on the single count in 2013. The final count of the season was on Mousa (3rd May), in perfect conditions but with birds difficult to flush and also flying back ashore again. However, three RSPB staff assisted with the count which, with a total of five observers keeping track of birds, was thought to have been as accurate as one could get and genuinely lower than in 2012.

26 Figure 2.3. Counts of adult Black Guillemots in northeast Mainland, at Levaneap (black), Kirkabister (blue), and Lunning (red), 1982-2014. Open symbols indicate the lower count when two were made in a year. Black symbols overlap 2004 and 2013, blue symbols in 1992, 1997, 2010 and 2013, red symbols in 2000 and 2010.

350

300

250

200

150

100

50

0 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

Figure 2.4. Counts of adult Black Guillemots in southeast Shetland, at Mousa (black), Boddam to Virkie (blue) and Aithsetter (red), 1982-2014. Open symbols indicate the lower count when two were made in a year. Black symbols overlap in 2000 and 2004, blue symbols overlap in 1993, 1997, 2006, 2007 and 2013, red symbols overlap in 1993, 2003 and 2007.

350

300

250

200

150

100

50 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

27 3. Moulting Common Eiders Somateria mollissima in Yell Sound and Sullom Voe

In the years between full censuses of moulting Common Eiders (the last was in 2012, the next is scheduled in 2015), counts are made at known traditional moulting locations in Yell Sound and Sullom Voe as well as around aquaculture sites in southern Yell Sound that have attracted moulting flocks in the past decade.

On 20th August southern Yell Sound was surveyed from land. Conditions were good, with a NW 4 wind and the sea calm. In Dales Voe, there was a flock of 28 female/juveniles and another of 62 female/juveniles and three adult males, both flocks at mussel lines in the middle of the voe off Scarvar Ayre. A flock of 55 birds at salmon cages in the mouth of Colla Firth could not be sexed due to light conditions. The only other birds seen were a female and two unfledged young at the head of Swining Voe, giving a total of 151 birds (Table 3.1).

On 21st August the SIC’s Humber RIB was used to survey the northern half of Sullom Voe, and Tinga Skerry, Little Holm and Muckle Holm in Yell Sound. Wind was NNE Force 1-2 at first, but had freshened to Force 3 by the time we finished, two hours later. In Sullom Voe, there were 18 males, 22 females (possibly including some fully-grown juveniles), and five unfledged juveniles feeding around and just offshore of the tanker jetties, six males feeding west of Ungam, two females and four juveniles in Voe of Scatsta, and a female with a fully-grown juvenile off Otter Loch, giving a total of 59 birds.

Clearly, the numbers of Common Eiders spending the summer and moulting in the area fluctuates from year to year, and a clearer picture will be obtained with another full census of Shetland in August 2015.

Table 3.1. Counts of moulting Common Eiders in Yell Sound and Sullom Voe, 2005-14 (nc = no count).

Area 2005 2006 2009 2010 2011 2012 2013 2014 Northern Yell Sound nc 0 3 nc nc 12 nc 0 Sullom Voe 11 0 4 nc nc 72 118 59 Southern Yell Sound 190 109 666 771 386 499 494 151 Total 201 109 673 771 386 583 612 210

28 4. Winter counts of seaduck and diving seabirds

4.1. Yell Sound and Sullom Voe

A lull in the weather allowed surveys by boat of most of the coastal waters of Yell Sound and Sullom Voe on 9-10th January (three observers). Conditions were generally good to excellent on both days. On 9th January the route followed the Mainland coast from the Ness of Setter, Lunna north to the Holms of Burravoe, then south along Yell from the Holm of West Sandwick to just north of Ulsta. On 10th January the standard route covered the Yell Sound islands (except Lamba, Little Holm and Muckle Holm), Orka and Sullom Voes, and southwest Yell, while an extension covered southeast Yell, from Orfasay east to Heoga Ness. For seaduck and grebes this represented complete coverage of suitable habitat within the Sullom Voe Harbour (SVH) area, and there was little likelihood of birds having moved location between the two days. For species that are more mobile or can feed in deeper water (divers, Cormorants, Shags and auks) the combined totals from the two days will probably be minima for the SVH area, although some individuals may have been recorded on both surveys. Results are tabulated according to coverage on comparable, previous surveys (Tables 4.1-4) and the combined totals for the two days are given in Table 4.4.

Table 4.1. Counts of seaduck and diving seabirds in Sullom Voe during winter.

Winter 2007/08 2008/09 2009/10 2010/11 2011/12 2012/13 2013/14 Date 15/11 27/12 10/12 12/2 21/12 16/1 23/1 10/1 Common Eider 0 2 0 2 0 2 0 0 Long-tailed Duck 2 1 0 0 0 1 1 2 Common Scoter 0 1 0 0 0 0 0 1 Velvet Scoter 0 0 0 0 1 0 0 0 Goldeneye 17 14 3 49 39 33 47 18 Red-breasted Merganser 72 65 131 121 194 74 124 141 Goosander 0 0 0 0 0 0 1 0 Red-throated Diver 4 2 4 0 0 1 2 1 Black-throated Diver 0 0 0 0 0 0 1 0 Great Northern Diver 7 6 2 1 5 2 3 8 Slavonian Grebe 19 26 25 31 18 29 21 32 Cormorant 20 7 27 7 62 5 18 8 Shag 219 145 420 119 732 87 90 158 Common Guillemot 0 0 0 0 0 1 0 2 Razorbill 2 1 0 0 0 1 2 1 Black Guillemot 49 59 68 49 145 121 195 156 Little Auk 1 0 0 0 0 1 0 0 Puffin 0 0 0 0 0 0 0 1 Total 414 329 680 379 1208 358 505 529

There were two main flocks of Common Eiders, one (37) at a large salmon farm off the Ness of Setter, Lunna, and one (41) at Sligga Skerry, north of Bigga. The largest (loose) groups of Long-tailed Ducks were off Outrabister, Lunna (28), east of Toft Ness (24), in the mouth of Orka Voe (17), and in the Wick of Copister, Yell (18). The low numbers of Goldeneye recorded probably reflects the mild winter, with birds able to utilise fresh water throughout. Apart from the relatively high number in Sullom Voe, the main concentration of Red-breasted Mergansers was in Dales Voe and Colla Firth (48), with smaller numbers along the Lunna coast (27), and in Gluss Voe (20); the total of 282 highlights the importance of the area for this species, both locally and nationally (UK threshold for a ‘site of national importance’ = ??).

Only small numbers of Red-throated Divers were recorded. While the eight Great Northern Divers in Sullom Voe was the highest count there in recent winters, just 17 were seen in Yell Sound, reflecting their continued scarcity since 1978/79 (the Esso Bernicia oil spill), when 131 were found oiled in the area in the first three months of 1979. In contrast, the 58 Slavonian Grebes recorded included birds at three locations with no recent records: Quey Firth (5), Burra Voe, North Roe (1), and Southladie Voe (2). There were two large flocks of Cormorants in Yell Sound, 190 roosting on Linga and 180 feeding in Quey Firth, while Shag and Black Guillemot remain the most numerous species of diving seabird in the SVH area in winter.

29

Table 4.2. Counts of seaduck and diving seabirds around the southern Yell Sound islands during winter. Count conditions: ** = moderate to good, *** = good or excellent throughout. For 10th January 2014, birds recorded to the east of the normal survey route in southeast Yell are indicated with a + sign.

Winter 2007/08 2008/09 2009/10 2009/10 2010/11 2011/12 2012/13 2013/14 Date 15/11 27/12 10/12 12/2 21/12 16/1 23/1 10/1 Count conditions *** *** *** *** ** *** *** *** Common Eider 35 68 12 70 19 55 27 57 Long-tailed Duck 100 164 105 47 46 80 98 73+3 Common Scoter 1 0 0 0 0 0 0 0 Velvet Scoter 0 0 0 0 0 0 0 1 Goldeneye 6 0 1 6 28 18 8 6 Red-breasted Merganser 1 12 17 8 0 13 13 5+11 Red-throated Diver 8 10 5 0 3 3 2 0+4 Great Northern Diver 8 9 2 2 2 5 3 2+1 Slavonian Grebe 0 0 0 0 5 3 6 4 Cormorant 464 335 322 361 484 104 353 230+1 Shag 1065 886 1444 1038 575 513 691 440+83 Common Guillemot 12 36 1 2 3 1 1 12+3 Razorbill 3 13 1 0 1 0 0 1 Black Guillemot 520 638 602 281 362 325 580 513+100 Little Auk 1 11 5 0 0 1 0 0 Puffin 0 0 0 0 0 0 4 0 Total 2224 2182 2517 1815 1528 1121 1786 1344+206

Table 4.3. Counts of seaduck and diving seabirds along the West Yell coast (Holm of West Sandwick to just north of Ulsta) during winter. Count conditions: *** = good or excellent throughout.

Winter 2001/02 2007/08 2013/14 Date 14/12 13/2 9/1 Count conditions *** *** ***

Long-tailed Duck 3 1 0 Velvet Scoter 1 0 0 Goldeneye 1 10 0 Red-breasted Merganser 0 24 7 Red-throated Diver 7 2 0 Great Northern Diver 0 4 3 Slavonian Grebe 0 0 2 Cormorant 0 2 2 Shag 349 77 40 Common Guillemot 15 5 2 Razorbill 0 1 0 Black Guillemot 58 27 71 Total 434 153 127

30 Table 4.4. Counts of seaduck and diving seabirds along the Mainland coast of Yell Sound during winter. Count conditions: ** = moderate to good, *** = good or excellent throughout. The final column gives the total for all areas of Yell Sound and Sullom Voe counted on 9-10th January 2014.

SW Yell Sound NW Yell Sound Mainland total TOTAL Winter 2007/08 2009/10 2013/14 2007/08 2013/14 2007/08 2013/14 2013/14 Date 13/2 13/12 9/1 13/2 9/1 13/2 9/1 9-10/1 Count conditions ** ** *** *** *** *** *** *** Common Eider 4 12 37 0 0 4 37 94 Long-tailed Duck 0 2 24 8 4 8 28 106 Common Scoter 0 7 0 0 0 0 0 1 Velvet Scoter 0 0 0 0 0 0 0 1 Goldeneye 11 10 4 6 0 17 4 28 Red-breasted Merganser 75 131 87 16 31 91 118 282 Red-throated Diver 18 0 0 1 6 19 6 11 Great Northern Diver 11 2 1 5 10 16 11 25 Slavonian Grebe 9 9 9 8 11 17 20 58 Cormorant 14 50 38 2 207 16 245 486 Shag 358 102 143 74 572 432 715 1436 Common Guillemot 18 0 5 4 17 22 22 41 Razorbill 4 0 0 6 2 10 2 4 Black Guillemot 101 111 185 52 191 153 376 1216 Puffin 0 0 0 1 4 1 4 5 Total 623 436 533 183 1055 806 1588 3794

31 4.2. Hascosay, Bluemull and Colgrave Sounds (HBC), and South Unst

The HBC area has been surveyed following a standard route since 1978/79, while the South Unst coast has been included on each survey since 2001/02. On 18th February (three observers), a light northeasterly breeze throughout freshened slightly at times, but this was not thought to have affected the detectability of flocks of seaduck (Table 4.5). Large numbers of Common Eider had been recorded in the area in February 2013, and the total recorded in February 2014 was very similar, and is probably the largest aggregation in Shetland during winter. Flocks were encountered feeding at ‘natural’ sites (e.g. 164 in Hascosay Sound) and at salmon cages (e.g. 343 off Sand Wick, Yell) but almost certainly move between these.

This area holds by far the largest concentration of wintering Long-tailed Ducks in Shetland (and probably one of the largest in the UK), but obtaining an accurate count has become more difficult as the species has changed behaviour. Formerly, the location of flocks was rather predictable as birds were (presumably) tied to feeding over certain types of seabed substrate at fairly shallow depths. For several years now, large numbers of Long-tailed Ducks have gathered in late winter and spring to display on the freshwater Loch of Belmont (they do not feed there) but this behaviour has now extended into mid winter, with flocks making flights from this loch to feed at aquaculture sites off south Unst, with no known diurnal pattern. During the February 2014 survey, Robbie Brookes monitored numbers on the Loch of Belmont (maximum 38, added to the survey total) while the survey boat was in the area; we recorded a large, mobile gathering over deep water between southwest Unst and Sound Gruney that could only be estimated at 480 birds, and the survey total is probably best described as 720 ± 50.

The number of Great Northern Divers wintering in Hascosay, Bluemull and Colgrave Sounds (HBC) declined during the mid 1980s, from counts of 54 and 61 in January and February 1983 to just 2, 3 and 4 on three surveys in winter 1986/87, and single figures only through the 1990s. Whether birds shifted their wintering distribution is unknown, but casual counts from land have recently found large numbers off southeast Unst in winter as well as spring, e.g. 50 off Muness (2-3 km north of the South Unst section of our survey route) on 8th February 2013, when just eight were counted on the HBC section and 10 off South Unst (Table 4.5). The number and general distribution on the February 2014 survey was the same as in 2013.

Relatively few Shags and Black Guillemots were counted in February 2014, although the detectability of the latter might have been reduced by the breeze, and the fact that some birds were in transitional moult which made them particularly hard to see.

Table 4.5. Counts of seaduck and diving seabirds in Hascosay, Bluemull and Colgrave Sounds, and off South Unst. Count conditions: ** = moderate to good, *** = good or excellent throughout.

Winter 2004/05 2005/06 2006/07 2007/08 2009/10 2011/12 2012/13 2013/14 Date 6/3 27/1 18/2 2/12 23/12 22/1 8/2 18/2 Count Conditions ** *** *** *** *** ** *** ** Common Eider 999 1001 1159 1241 1084 978 1458 1394 King Eider 1 0 0 0 0 0 0 2 Long-tailed Duck 313 200 161 144 317 365 555 720 Common Scoter 0 2 1 0 3 1 2 4 Velvet Scoter 2 0 0 0 0 0 0 1 Goldeneye 9 14 4 7 25 11 12 0 Red-breasted Merganser 2 8 15 17 13 36 26 20 Red-throated Diver 7 5 51 12 16 20 21 12 Great Northern Diver 7 1 9 23 17 9 18 18 White-billed Diver 0 0 1 0 0 0 1 0 Cormorant 80 116 263 96 90 252 243 157 Shag 295 871 1243 1496 569 554 804 306 Common Guillemot 3 47 10 3 2 2 6 13 Razorbill 0 0 2 0 0 0 1 1 Black Guillemot 294 541 359 367 506 277 885 364 Puffin 0 0 0 0 0 1 0 0 Total 2012 2806 3278 3406 2642 2506 4032 2974

32 4.3. Rova Head to Kirkabister, East Mainland

This coast comprises the sheltered inlets of Dales Voe, Lax Firth, Wadbister Voe and Cat Firth, all of which host aquaculture, the more exposed coasts of South and North Nesting, and a series of offshore shallows and skerries. A survey on 17th February (three observers) was in good to excellent conditions with a very light westerly air, no swell, and thin, high cloud (Table 4.6). The few Common Eiders seen were in small, scattered groups, both at salmon cages and offshore skerries, while the main concentration of Long-tailed Ducks (94) was at the usual feeding ground between Glet Ness and the Aswick Skerries. The count of Red- breasted Mergansers was at the lower end of the 100-200 range recorded along this coast in recent winters.

All Red-throated Divers seen were still in winter plumage, and included a group of 12 in Dock of Lingness, South Nesting. The excellent light conditions will have contributed to the high count of Great Northern Divers, but many were very close inshore, mostly as singles or in pairs, although there were four tight groups of five birds, and a remarkable flock of 18 in the South Wick of Eswick. The distribution of Slavonian Grebes was eight in Dales Voe, 12 in Lax Firth, 23 in the Wadbister/Cat Firth area, two in South Voe of Gletness, and one in West Voe of Skellister; these have all been regular locations in recent winters. The totals for Cormorant, Shag and Black Guillemot were unremarkable, while some of the Common Guillemots and Razorbills seen appeared to be in poor condition.

Table 4.6. Counts of seaduck and diving seabirds along the coast from Rova Head (north Bressay Sound) to Kirkabister (North Nesting) during winter. Count conditions: *** = good to excellent throughout.

Winter 2006/07 2007/08 2008/09 2009/10 2010/11 2011/12 2012/13 2013/14 Date 28/12 10/2 9/2 11/12 27/1 19/12 30/11 17/2 Count Conditions *** *** *** *** *** *** *** *** Common Eider 158 136 163 204 125 126 93 59 Long-tailed Duck 79 119 125 164 98 119 134 161 Common Scoter 0 3 2 4 0 3 0 0 Velvet Scoter 0 2 0 0 0 0 0 0 Goldeneye 15 30 39 37 46 31 27 16 Red-breasted Merganser 169 92 197 117 116 181 126 101 Goosander 0 0 6 1 0 0 0 0 Red-throated Diver 20 54 2 0 5 20 10 43 Great Northern Diver 64 69 79 113 45 107 94 103 White-billed Diver 0 0 1 0 0 0 0 0 Slavonian Grebe 32 42 43 49 61 57 48 46 Cormorant 66 10 98 5 115 69 41 52 Shag 852 436 543 507 327 515 382 419 Common Guillemot 12 19 32 11 14 8 47 43 Razorbill 18 16 1 0 0 3 4 7 Black Guillemot 198 362 433 603 336 422 409 281 Little Auk 59 1 0 2 0 0 0 0 Puffin 1 3 0 0 0 4 0 1 Total 1743 1394 1764 1817 1288 1665 1415 1332

33 4.4. Bressay Sound and North Bressay

The area was surveyed (two observers) in perfect conditions on 19th February (Table 4.7). The number of Common Eiders wintering in the area has declined considerably since the mid 2000s; 104 birds were recorded in Bressay Sound itself, the remainder being in scattered groups in the bays to the south (Brei Wick, Voe of Sound and Gulber Wick), and around Score Head on Bressay. More Long-tailed Ducks were present than on the three previous surveys, but the count of Red-breasted Mergansers was relatively low. The 17 Great Northern Divers were in Voe of Cullingsbrough (5), Aith Voe (3), Bressay Sound (1), Brei Wick (3), Voe of Sound (3) and Gulber Wick (2). Few Cormorants appear to winter in this area, and the count of Shags was also rather low.

Table 4.7. Counts of seaduck and diving seabirds in Bressay Sound (Gulber Wick to Rova Head) and North Bresssay (Whitehill to Voe of Cullingsbrough). Count conditions: ** = moderate to good, *** = good to excellent throughout.

Winter 2005/06 2007/08 2009/10 2011/12 2012/13 2013/14 Date 28/1 14/11 3/2 3/2 12/12 19/2 Count conditions ** *** ** *** ** *** Common Eider 528 249 253 223 99 150 Long-tailed Duck 142 126 82 61 84 127 Common Scoter 0 0 1 4 1 3 Goldeneye 14 0 34 1 3 2 Red-breasted Merganser 43 41 38 44 23 16 Red-throated Diver 4 1 0 11 0 9 Great Northern Diver 5 10 2 9 9 17 Slavonian Grebe 0 0 3 2 0 0 Cormorant 5 7 15 3 1 5 Shag 414 432 374 234 359 150

Common Guillemot 58 7 3 9 11 20

Razorbill 12 10 4 18 0 7 Black Guillemot 271 394 381 358 302 326 Little Auk 0 3 0 19 0 0 Puffin 1 4 0 0 0 0 Total 1497 1284 1191 997 892 887

34 4.5. Whiteness Voe to Skelda Voe, West Mainland

This area was counted from land by Paul Harvey (Shetland Amenity Trust) on 7th February (Table 4.8). Few Common Eiders were seen and the count of Long-tailed Duck was the lowest on record (Figure 4.1), with none seen in The Firth at Tresta. In contrast, the 188 Red-breasted Merganser seen was only just exceeded by a count in February 2008; the largest concentrations were 59 in Weisdale Voe and 41 in each of Whiteness Voe and The Firth. The number of Great Northern Divers recorded on these counts declined during the late 1990s and early 2000s (Figure 4.2), but has fluctuated since, and the February 2014 count was the highest since winter 1999/2000. While the count of Slavonian Grebes was similar to that in December 2012, the distribution differed with none seen in Sand or Seli Voes. While this species tends to be seen in the same feeding areas, individuals probably move between neighbouring voes within a winter, and birds may have moved from these rather exposed voes to more sheltered locations in the January gales. These gales were probably responsible for the high count of Common Guillemots sheltering in the area.

Table 4.8. Counts from land of diving seabirds and seaduck in the voes between Whiteness Voe and Skelda Voe. Count conditions were good to excellent throughout on each date.

Winter 2005/06 2006/07 2007/08 2009/10 2010/11 2011/12 2012/13 2013/14 Date 1/2 7/2 19/2 12/2 25/1 23/1 13/12 7/2 Common Eider 142 179 178 201 169 58 317 42 King Eider 1 0 0 0 0 0 0 0 Long-tailed Duck 30 38 47 46 33 36 26 23 Common Scoter 0 0 0 4 3 5 0 2 Velvet Scoter 0 0 2 0 0 1 0 0 Goldeneye 17 20 16 35 11 21 18 28 Red-breasted Merganser 145 134 192 156 83 110 156 188 Goosander 0 0 0 2 1 3 0 1 Smew 0 0 0 1 0 0 0 0 Red-throated Diver 1 4 13 0 1 1 2 3 Black-throated Diver 0 0 0 0 0 0 0 1 Great Northern Diver 11 14 23 15 26 39 17 42 Slavonian Grebe 52 67 68 77 73 74 55 57 Cormorant 8 9 35 26 14 10 17 27 Shag 115 73 127 101 103 104 145 127 Common Guillemot 15 0 6 6 0 0 0 76 Razorbill 7 3 9 0 1 0 3 11 Black Guillemot 75 64 108 57 76 76 44 106 Puffin 0 0 0 0 0 0 0 1 Total 619 605 824 727 587 528 800 735

Figure 4.1. Counts from land of Long-tailed Duck and Red-breasted Mergansers in the voes between Whiteness Voe and Skelda Ness.

150 200 Long-tailed Duck Red-breasted Merganser 125 150 100

75 100

50 50 25

0 0

35 Figure 4.2. Counts from land of Great Northern Divers and Slavonian Grebes in the voes between Whiteness Voe and Skelda Ness.

60 80 Great Northern Diver 50 70 Slavonian Grebe 60 40 50 30 40 20 30 20 10 10 0 0

4.6. Vaila Sound and Gruting Voe

This large area of sheltered inshore waters was survey from land by Rory Tallack (Shetland Amenity Trust) on 7th February. Systematic counts have been opportunistic and infrequent in the past as the area holds relatively few diving seabirds and seaduck, although flocks of several hundred Common Eiders are known to be attracted to aquaculture sites at different times of the year. The single Great Northern Diver seen was in Wester (Vaila) Sound, while Slavonian Grebes were recorded in Gruting Voe (2), Voe of Browland (3) and Olas Voe (4). Despite the rather few birds wintering the area, it is worth continuing systematic counts if the opportunity arises, in order to update information for oil spill contingency planning purposes.

Table 4.9. Counts from land of diving seabirds and seaduck in the Vaila Sound and Gruting Voe area. Count conditions: ** = moderate to good, *** = good to excellent throughout.

Winter 1990/91 1997/98 1999/00 2001/02 2009/10 2013/14 Date 14/2 24/1 24/1 25/1 13/2 7/2 Count conditions *** ? *** ** *** *** Common Eider 8 0 1 6 66 7 Long-tailed Duck 0 0 1 0 0 0 Common Scoter 0 0 0 0 0 4 Goldeneye 62 5 13 7 2 0 Red-breasted Merganser 20 20 27 0 32 15 Goosander 0 6 0 0 0 5 Red-throated Diver 1 2 0 0 0 1 Great Northern Diver 0 3 2 0 0 1 Slavonian Grebe 0 3 3 9 5 9 Cormorant 0 1 3 0 8 15 Shag 154 51 37 45 124 81 Common Guillemot 12 31 12 1 2 22 Razorbill 6 5 1 0 0 1 Black Guillemot 101 64 70 17 205 73 Little Auk 0 0 0 1 0 0 Total 364 191 171 86 444 234

36 5. Beached Bird Surveys

This was the 36th consecutive year of the monthly beached bird survey in Shetland, which is carried out by the authors and a team of volunteers (see Acknowledgements). Coverage includes Unst, north and east Yell, south Fetlar, west Bressay, Fair Isle, 49 beaches on Mainland, mainly on the ‘outer’ coast, as well as 15.6 km of shoreline in the northern half of Sullom Voe, and nine other beaches (totaling 5.2 km) in Yell Sound.

5.1. Incidence of oiling

Only 11 seabirds were found oiled in 2014, the lowest number since 2005 (Table 5.1). The species involved were Fulmar (6), Gannet (1), Shag (1), Lesser Black-backed Gull (1), Herring Gull (1) and Razorbill (1). There was no obvious temporal or geographic pattern to their occurrence, and all but one Fulmar were very lightly contaminated and could have survived for some time and travelled a considerable distance after having become oiled. The only oiled corpse in the Yell Sound area was a Fulmar at the Ness of Bardister (just south of Gluss Ayre) in June. In addition to the 11 oiled seabirds, a Gannet at Fair Isle in June was contaminated with an unidentified sticky substance, possibly polyisobutylene or similar.

Four samples of oiled plumage were analysed (Table 5.3). Two were of fuel oil residues, including one from a Shag at Nesbister, Whiteness Voe in July. An adult Lesser Black-backed at Sandwick, east Unst in April lightly oiled with East Shetland Basin crude was only the eighth individual of this scarce species to be recorded oiled since 1980, and the first since May 1999. Oil on a Fulmar at Culswick, west Mainland in November was typed as Russian crude in origin, although it was possible that it had been refined without thermal cracking and used as fuel oil.

Table 5.1. Annual summary details for the Shetland Beached Bird Survey, 2005-14. Total figures are from March 1979 to October 2014.

Year Km. Corpses Oiled Total/km % Oiled Oiled/km. 2005 578.80 1,370 9 2.367 0.66 0.016 2006 551.50 1,086 17 1.969 1.57 0.031 2007 559.40 1,069 36 1.911 3.37 0.064 2008 577.80 1,159 90 2.006 7.77 0.156 2009 553.90 942 40 1.701 4.25 0.072 2010 551.30 857 46 1.555 5.37 0.083 2011 577.80 935 23 1.618 2.46 0.040 2012 579.20 1031 21 1.780 2.04 0.036 2013 581.12 811 49 1.396 6.04 0.084 2014 587.52 1,152 11 1.961 0.96 0.019 TOTAL 21,134.14 69,419 4,706 3.285 6.78 0.224 5-Year Annual Means: 1979-1983 4.064 9.98 0.408 1984-1988 3.933 7.86 0.311 1989-1993 3.990 7.19 0.285 1994-1998 4.307 9.50 0.409 1999-2003 3.171 2.39 0.073 2004-2008 2.163 2.97 0.061 2009-2013 1.610 4.04 0.063 2014- 1.961 0.96 0.019

37 Table 5.2. Seabirds and seaduck found on beached bird surveys in 2014. For each species the first figure is the total found, the second the number that were oiled (in bold). Other species: Tundra Bean Goose (1), Greylag (25), Wigeon (1), Mallard (4), Oystercatcher (11), Lapwing (2), Curlew (3), Woodcock (2), Turnstone (1), Rock Dove (12), Long-eared Owl (1), Hooded Crow (5), Raven (1). Net/rope/hook tangled: Fulmar (1 fish net, 1 rope, 1 fish hook); Gannet (4 fish net, 6 rope); Herring Gull (1 fish hook). *Figures for km surveyed are rounded to one decimal point from a figure of 49.46 km for a complete monthly survey; beaches with nesting terns are not surveyed in May, June and July.

SPECIES J F M A M J J A S O N D SUM Common Eider 0 2 1 1 0 3 0 2 0 0 2 2 13 Long-tailed Duck 0 0 1 0 0 0 0 0 0 0 0 0 1 Red-throated Diver 0 0 0 0 1 1 0 0 0 0 0 0 2 Great Northern Diver 0 1 0 0 0 0 0 0 0 0 0 0 1 Fulmar 13 27 21 31/2 38/1 34/1 61 53/1 13 9 7/1 8 315/6 Gannet 6 4 8 5/1 4 9 8 8 4 7 10 3 76/1 Cormorant 0 3 1 0 0 1 2 0 0 0 1 0 8 Shag 13 22 11 15 2 3 8/1 5 1 1 1 2 84/1 Arctic Skua 0 0 0 0 1 0 0 0 0 0 0 0 1 Great Skua 0 0 0 0 3 0 0 0 0 1 0 0 4 Black-headed Gull 0 0 0 0 0 0 3 3 1 0 0 0 7 Common Gull 3 1 2 0 1 4 10 5 3 0 1 0 30 Lesser Bl.-backed Gull 0 0 0 1 1 0 2/1 1 1 0 1 0 7/1 Herring Gull 11 9 4 6 8/1 5 6 7 4 2 2 3 67/1 Glaucous Gull 0 1 0 0 0 0 0 0 0 0 0 0 1 Great Bl.-back. Gull 9 18 7 7 7 6 8 3 0 0 0 0 65 Kittiwake 17 9 2 4 4 0 2 7 0 0 4 1 50 Common Tern 0 0 0 0 0 0 0 1 0 0 0 0 1 Arctic Tern 0 0 0 0 0 1 7 0 1 0 0 0 9 Common/Arctic Tern 0 0 0 0 0 1 0 1 0 0 0 0 2 Common Guillemot 21 112 91 43 26 11 7 2 4 0 0 0 317 Razorbill 4/1 19 3 1 6 2 3 1 1 0 0 0 40/1 Black Guillemot 2 6 5 0 3 4 3 1 1 0 1 0 26 Little Auk 2 0 0 0 1 0 0 0 0 0 1 0 4 Puffin 2 5 0 0 3 4 5 1 1 0 0 0 21

Total 103 239 157 114 109 89 135 101 35 20 31 19 1152 Oiled 1 0 0 3 2 1 2 1 0 0 1 0 11 Km. surveyed* 49.0 49.4 49.4 49.4 48.0 47.6 47.7 49.5 49.5 49.5 49.5 49.5 587.52 Corpses / km. 2.10 4.84 3.18 2.31 2.27 1.87 2.83 2.04 0.71 0.40 0.63 0.38 1.961 % Oiled 1.0 0 0 2.6 1.8 1.1 1.5 1.0 0 0 3.2 0 0.955 Oiled / km. 0.02 0 0 0.06 0.04 0.02 0.04 0.02 0 0 0.02 0 0.019 Oiled after death 0 0 0 0 0 0 0 0 0 0 0 0 0 Net/rope/hook tangled 1 0 1 1 1 1 1 0 1 3 4 0 14 Other species 2 5 2 6 8 3 18 8 3 2 10 2 69

Table 5.3. Results of analyses by Fugro (ERT Scotland) Ltd of oil samples collected in 2014. S = slightly oiled (< 10%); M = moderately oiled (10-25%).

No. Date Location Sample Type Possible type; source 236 25/4 Culswick, W Mainland Fulmar S Fuel Accidental release or illegal bilge discharge 237 28/7 Nesbister, W Mainland Shag S Fuel Accidental release or illegal bilge discharge 238 1/8 Sandwick, Unst LBB Gull S Crude Indicative of East Shetland Basin; tank washing or accidental release 239 27/11 Sand, W Mainland Fulmar M Crude Russian; possibly refined without thermal cracking and used as fuel oil; tank washing, accidental release or illegal bilge discharge

38 5.2. Non-oiled mortality

After eight winters with few Guillemots being found dead on beaches, 112 were recorded at the end of February following persistent south-easterly gales, and a further 91 were found on the March survey (Figure 5.1). At this time of year, first-winter Guillemots can be distinguished from older birds by having white tips to the greater underwing coverts (although this is not 100% reliable), and also by having a thinner, paler bill and by leg colour. On this basis, < 25% of those found in February and March were first-winter birds (Table 5.4). By late February, most adult Guillemots would have completed their moult into summer plumage or nearly done so, and virtually all would have done so by late March. Volunteers had not been asked to record moult, and as dead birds were scavenged quickly and only a minority had the head present, the sample size for checking this was small (Table 5.5). However, birds in summer plumage and with no white tips to the greater underwing coverts predominated in both months, and were almost certainly of breeding age. Beached bird surveys after prolonged gales such as in February 2014 may underestimate mortality compared to after calmer periods because the vast quantity of kelp thrown up can both hide some corpses and prevent others washing ashore. Scavengers also quickly realise that dead birds are washing ashore, and especially on the February survey gulls were seen feeding on corpses just offshore, while flocks of Ravens and Hooded Crows were present on many beaches and in some cases were seen carrying seabird remains inland. Although more Guillemots were found dead in February and March 2014 than in recent winters, many more were found during winters in the 1980s and 1990s (Figure 5.2); that none was oiled in 2014 is also noteworthy.

Figure 5.1. The number of Guillemots (upper, per km), Razorbills (middle, per 10 km) and Puffins (lower, per 10 km) recorded on monthly beached bird surveys, January 2005 to December 2014. 2.5

2.0 Guillemot oiled 1.5 Guillemot clean

1.0

0.5

0.0

6.0 5.0 Razorbill oiled x10 4.0 Razorbill clean x10 3.0 2.0 1.0 0.0

4.0

Puffin oiled x10 3.0 Puffin clean x10 2.0

1.0

0.0

39 Table 5.4. Age composition of Common Guillemots found on the 2014 beached bird surveys. No white tips to the greater underwing coverts means birds were older than their first year, white tips means they were in their first winter year. Those in April – June with white fringes were in summer plumage and older than first-year birds. Percentages given are of the total of aged corpses only.

Month January February March April May June Guillemot No. % No. % No. % No. % No. % No. % No white tips 14 70 81 74 72 79 31 80 18 82 8 80 White fringes 0 0 2 2 3 3 2 5 3 14 1 10 White tips 6 30 26 24 16 18 6 15 1 5 1 10 Unaged 1 3 0 4 4 1 Total 21 112 91 43 26 11 Month July August September October November December Guillemot No. % No. % No. % No. % No. % No. % No white tips 6 86 1 50 4 100 0 0 0 White fringes 0 0 0 0 0 0 0 0 0 White tips 1 14 1 50 0 0 0 0 0 Unaged 0 0 0 0 0 0 Total 7 2 4 0 0 0

Table 5.5. Head plumage of Common Guillemots aged by greater underwing covert pattern: no white tips (NWT, probably second-winter or older), white fringes (WFr, age uncertain), white tips (WT, probably first- winter).

February 2014 March 2014 Head plumage NWT WFr WT NWT WFr WT Summer 16 0 0 26 1 0

Transition 3 1 0 5 1 0

Winter 7 1 3 5 0 6

Unknown 55 0 26 36 1 10

Figure 5.2. The total number of Common Guillemots found per km on beached bird surveys during each winter (October to March), 1979/80 to 2013/14.

4

Guillemot oiled 3 Guillemot clean 2

1

0

Of the 26 Razorbills found dead on the January to March surveys, nine were first-winter (based on bill grooves), six were adults (including one large bird with a wing length of 210 mm), and 11 were headless and could not be aged. Two of the six Puffins found were also headless and could not be aged, one was a first- winter and three were adults.

40 The late winter gales may also have had an impact on two inshore seabird species. Although the total of 13 Black Guillemots (11 adults, 2 first-winters) found on the January to March surveys may not seem high, few are normally found in late winter, this was nine times the average number found in those three months during 2000-13 (Figure 5.3), and this small species is even more likely to be overlooked among mounds of kelp than the larger Guillemots. The 61 Shags (41 adults, 16 immatures, 4 unaged) found on the January to April surveys may not have equaled the numbers found in early 2003 (when the population was higher) or 2011, but was eight and three times the number found in 2013 and 2012, respectively (Figure 5.4).

Figure 5.3. The number of Black Guillemots found per km on the January to March beached bird surveys, 2000-2014.

0.10

0.08

0.06

0.04

0.02

0.00 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Figure 5.4. The number of Shags found per 10 km on the January to April beached bird surveys, 1980-2014.

6 Unaged 5 Immature Adult 4

3

2

1

0

The early winter period was notable for the lack of pelagic auks, with no Common Guillemots, Razorbills or Puffins recorded and only a single Little Auk found on the October, November and December surveys.

41 6. 2014 Publications and Presentations

Heubeck, M., Gear, S. & Harris, M. P. 2014. A photographic resurvey of seabird colonies on Foula, Shetland. Scottish Birds 34: 291-302. Heubeck, M. Oil Spill Population Impact Assessment. Powerpoint presentation at UK oiled wildlife preparedness and response workshop, Oil & Gas UK, Aberdeen, 20th October 2014.

7. Acknowledgements

Gary Bell, Paul Harvey, Rory Tallack, Brydon Thomason and Howard Towll assisted with winter seabird surveys; thanks also to boatman Jonathan Wills (Dunter III). Paul Harvey and Roger Riddington also helped with counts of Shags and Kittiwakes during June. The following participated in the beached bird survey during 2014: Richard Ashbee, Gary Bell, Juan Brown, Andy Cook, Martha Devine, Harry Edwards, Dick Foyster, Andy Gear, Liz Gillard, Paul Goddard, Newton Harper, Derick Herning, Sally Huband, Cecilia James, Logan Johnson, Micky Maher, Helen Moncrieff, Rebecca Nason, Dave Okill, David Parnaby, Mike Pennington, Roger Riddington, Malcolm Smith, Jonathan Swale, Brydon Thomason, Howard Towll and Glen Tyler.

8. Erratum: Ornithological Monitoring Programme in Shetland, Annual Report 2013

Missing from the list of beached birds found in April 2013 were an adult Great Black-backed Gull and three Common Guillemots (1 NWT, 1 WT, 1 unaged), none of which were oiled. Tables (6.1, 6.2, 6.4) and text affected by this have been corrected in the copy of the report available online (http://www.soteag.org.uk).

The Ornithological Monitoring Programme is funded by the Sullom Voe Association Limited.

42 Appendix 1. Seabird monitoring on Foula in 2014, conducted by the Foula Ranger Service (Sheila and Penny Gear, and Fran Dyson Sutton), summarised by Martin Heubeck.

Common Eider. A count along the east coast of Foula on 27th July recorded 168 adults, a similar number to 2012-13, while mean brood size was higher than in 2013 (*the 2009 chick total includes three newly hatched seen on 9th August).

16/7/05 22/7/06 27/7/07 26/7/08 27/7/09 24/7/10 26/7/11 27/7/12 25/7/13 27/7/14 Males 102 82 73 94 110 48 74 108 94 81 Females 81 61 60 70 89 66 51 50 71 87 Adults 183 143 133 164 199 114 125 158 165 168 Chicks 44 37 27 25 53* 19 26 81 27 49 Total 227 180 160 189 252 133 151 239 192 217 Brood/1 3 7 11 8 10 8 7 7 15 5 Brood/2 6 8 4 7 12 3 6 12 3 11 Brood/3 7 2 1 1 4 0 1 8 2 6 Brood/4 2 2 0 0 1 0 1 4 0 1 Brood/5 0 0 1 0 0 1 0 2 0 0 Mean Br. 2.44 1.95 1.59 1.56 1.85 1.58 1.73 2.45 1.35 2.13

Red-throated Diver. Both the number of sites occupied and breeding attempts were at the same high level as in 2013, but the number of chicks hatched and those surviving to presumed fledging were the highest since monitoring began. There was no sign of predation around fledging, but one fledging (included in the total) was subsequently seen with an injured wing, and later found dead. One fledgling was leucistic.

Foula Red-throated Divers 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Sites occupied at least once 11 13 11 10 12 10 13 12 13 13 Breeding attempts 9 9 7 8 11 9 11 8 12 12 Sites where chicks hatched 7 7 6 6 7 5 7 6 7 11 Minimum number of chicks 11 9 7 6 10 5 9 8 9 17 Chicks presumed fledged 7 3 7 4 9 4 5 5 4 15 Breeding success 0.78 0.33 1.00 0.50 0.82 0.44 0.45 0.63 0.33 1.25

Northern Fulmar. Four of the Fulmar plots were picked at random and monitored by Sheila Gear. The birds had a good season and productivity was high. Using birds present on possible nest sites on all three observations at the beginning of June (1st, 5th, 7th) as the criteria for apparently occupied sites (AOS), mean productivity was 0.67 fledglings per AOS. However, one third of fledglings (33) were at AOS which had birds present on less than three of these dates, including three at sites where no birds were observed on any of the three dates. This would suggest that birds were not attending their nest sites very well at the beginning of June.

Plot Total AOS on all 3 Chicks at 3-check Success AOS checks (%) sites + ‘extra’ 1 83 34 (41.0%) 14 + 6 20/40 = 0.50 3 58 30 (51.7%) 18 + 8 26/38 = 0.68 5 51 23 (45.1%) 12 + 14 26/37 = 0.70 6 46 26 (56.5%) 20 + 5 25/31 = 0.81 Sum 238 113 (47.5%) 64 + 33 97/146 = 0.66 Mean 48.6% 0.67 ± 0.13 SD

43 European Shag. Shag numbers around the island were extremely low and many former breeding areas remained deserted. A count right round the island on 19th May in fine conditions gave a total of only 284 birds, most of which were on the east coast. However, those birds that did breed had a very successful season. Four of the eight original breeding success plots (which in total held 70 nests in 2001) were deserted, there were ten nests in the other four, and 25 nests in two added since 2008; all progressed to incubation. Breeding success at 1.89 young fledged per incubating nest was the highest on record for Foula, and included ten pairs that successfully fledged three chicks.

Shag 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Trace nests 1 3 3 3 2 1 0 4 3 0 Empty nests 1 0 1 10 2 1 1 3 4 0 Incubating nests 6 33 24 27 44 41 27 10 4 35 % Incubating 75.0 91.7 85.7 67.5 91.7 95.3 96.4 58.8 36.4 100 Young fledged 0 35 25 7 55 56 20 5 3 66 Fledged / inc. 0.00 1.06 1.04 0.26 1.25 1.37 0.74 0.50 0.75 1.89

Arctic Skua. Although the first bird was seen on 29th April, most did not return until mid May. There were 24 AOTs on the island, but only 21 pairs were seen to have laid. Mean clutch size was 1.70. A total of 22 identifiable colour-ringed birds were seen, 17 of which were seen in 2013, three had not been seen since 2012, one not since 2011 and one not since 2010, giving the impression that there may be a pool of birds still alive that might return to breed if conditions improve. Twelve colour-ringed birds, unidentifiable because of missing rings, were also seen. No immature birds were seen. Despite the season being very late, with most chicks not flying until the beginning of August, 18 chicks fledged. Productivity was the highest recorded for many years. Very unusually, no predation of fledglings by Great Skuas was observed and only two ringed chicks did not survive.

Arctic Skua 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 First seen 20/5 26/4 26/4 21/4 24/4 26/4 22/4 3/5 29/4 AOT 68 79 71 41 63 50 41 37 35 24 Pairs laid 18 61 42 10 49 39 32 27 26 21 Mean clutch ? 1.68 ? 1.71 1.43 1.73 1.63 1.58 1.77 1.70 Fledged 1 2 0 0 22 (1) 0 4 0 18 Success/AOT 0.01 0.03 0 0 0.35 0.00 0 0.11 0 0.75

Great Skua. The first birds were seen on 10th April but most did not return until May. The sample plot in the Bitten was monitored and the number of AOTs was slightly higher than in 2013. Mean clutch size was 1.88, higher than in 2013 (1.54). At the end of the first week of July, cannibalistic predation of chicks began and only 15 chicks were still surviving at ringing age. Seven of these were subsequently found predated and 8 survived to fledge. Productivity was 0.17 chicks per pair at fledging, although predation continued after fledging.

Common Gull. A total of 20 adults attended the breeding colony at the Groups quarry, but only six pairs laid. Three pairs failed around hatching (4–7th June) and the other three pairs fledged six chicks.

Herring Gull. Fourteen adults were present at the small colony at da Swaa and six pairs were seen to lay. Only six chicks were observed but they all fledged.

Black-legged Kittiwake. A whole island count from the sea in good conditions on 7th June recorded a total of 361 apparently occupied nests, 10% more than in 2013 and only slightly less than in 2012.

Black-legged Kittiwake 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Census count (AON) 898 1065 997 - 509 582 480 378 327 361

44 Kittiwakes again had a late breeding season, although at most sub-colonies it was the most successful for many years. The monitored sub-colony In Under da Stee was an exception. Only a possible four pairs were seen to have laid, although some other adults were observed at last year’s nests, only one downy chick was seen, only four adults were present on 1st July and none were there on 19th July; a small cliff fall occurred here on 9th August. The sub-colony at Hodden was more typical of the island as a whole. Although most nests were washed away by heavy rain on 9th August, the chicks survived and redistributed on the ledges. Productivity was 0.83 chicks fledged per well-built nest.

In under da Stee 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Completed nests 106 118 91 13 70 52 50 44 32 20 Fledged 27 26 1 0 23 3 0 0 0 0 Success 0.25 0.22 0.01 0 0.33 0.06 0 0 0 0 Hodden 2008 2009 2010 2011 2012 2013 2014 Completed nests 2 46 31 22 20 18 18 Fledged 0 22 0 2 0 0 15 Success 0 0.48 0 0.09 0 0 0.83 Mean success 0 0.41 0.03 0.05 0 0 0.42

Arctic Tern. Adults again returned late, arriving in mid May. Fluctuating numbers, maximum c. 40, were seen throughout the summer, around the Voe area and sometimes a few at the south end of the island but only three pairs attempted to breed, at the Clettins; two chicks fledged. Adults remained until mid August.

Common Guillemot. Guillemots returned late and numbers were low. Some birds were still incubating in July, but chick survival to fledging appeared higher than last year. Chicks were fed mainly small Pollack and Saithe, and no adults were seen carrying sandeels.

Black Guillemot. Two counts along the east coast were in generally favourable conditions. The higher count of adults (160), split between the mornings of 3rd and 7th May, was only slightly lower than in 2013 (166, but probably affected by choppy conditions) but 13% lower than the peak count of 184 in 2012.

Area counted Date & time Weather & tide Count East coast N & S 27/4: 7.15–9.30am ESE 3 sun, light swell, some chop, tide high and ebbing 157 adults East coast S 3/5: 7.40–9.35am SE 3, sun, no swell, tide flooding 71 adults East coast N 7/5: 7.00–8.40am NE 3, cloud, light to moderate swell, tide ebbing 89 adults

Figure A.1. Counts of adult Black Guillemots along the east coast of Foula, 1996-2014. Open symbols indicate the lower count when two were made in a year.

200

175

150

125

100

75 1996199719981999200020012002200320042005200620072008200920102011201220132014

Atlantic Puffin. Adults were late back, with few onshore before mid May. Numbers were low, except when the non-breeders arrived in July. By mid July, adults were bringing in good amounts of a wide range of fish species, including small Ling and clupeids, but none were seen with sandeels. Burrow occupancy on the transect in Under da Stee on 14th June was 60 occupied, 33 unoccupied; no dead chicks were seen.

45