Investigation of the Utilisation of Sea Space by Sea Birds in the Pentland Firth & Orkney Area 2012 / 13

SCOTTISH GOVERNMENT

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YEAR 2: INVESTIGATION OF THE UTILISATION OF SEA SPACE BY SEA BIRDS IN THE PENTLAND FIRTH & ORKNEY AREA 2012 / 13

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FINAL REPORT

August 2013

APEM REF: 511639

CLIENT: Scottish Government

ADDRESS: The Scottish Government Victoria Quay Edinburgh EH6 6QQ

PROJECT No: 511639

th DATE OF ISSUE: 27 August 2013

PROJECT DIRECTOR: Dr Stuart Clough

PROJECT MANAGER: Dr Nicola Goodship

PROJECT AUTHORS: Dr Nicola Goodship, Dr Stephanie McGovern, Dr Emily Barlow and Dr Mark Rehfisch.

Report should be cited as APEM (2013) Year 2: Investigation of the utilisation of sea space by sea birds in the Pentland Firth & Orkney area 2012 / 13. Report to Scottish Government. 246 pp.

APEM LTD- Head Office APEM LTD- Edinburgh Office Riverview, Room 1, Section A A17 Embankment Business Park, The Technopole Centre, Heaton Mersey, Stockport SK4 3GN Edinburgh Technopole, Milton Bridge, Tel: 0161 442 8938 Fax: 0161432 6083 Nr Penicuik, Midlothian, EH26 0PJ

Registered in England No. 2530851 Website: www.apemltd.co.uk APEM Final Report 511639

CONTENTS EXECUTIVE SUMMARY ...... V 1. ABBREVIATIONS ...... VI 2. INTRODUCTION ...... 1 3. AIMS & OBJECTIVES ...... 3 4. METHODS ...... 4

4.1. SURVEY OUTLINE ...... 4 4.2. SURVEY TIMINGS ...... 4 4.3. SURVEY DESIGN ...... 5 4.4. SURVEY COVERAGE ...... 5 4.5. DATA PROCESSING AND QUALITY ASSURANCE ...... 8 4.6. DATA ANALYSIS ...... 9 4.6.1 DESIGN-BASED ABUNDANCE ESTIMATES ...... 9 4.6.1.1 Abundance estimates ...... 9 4.6.1.2 Confidence limits ...... 10 4.6.1.3 Precision ...... 11 4.6.2 RELATIVE DENSITY DISTRIBUTION MAPS ...... 11 4.7. WEATHER CONDITIONS...... 11 5 RESULTS ...... 15

5.1 ABUNDANCE ESTIMATES AND DISTRIBUTION OF BIRD SPECIES / GROUPS ...... 15 5.1.1 MUTE SWANS ...... 15 5.1.2 GREYLAG GEESE ...... 18 5.1.3 TOTAL DUCKS ...... 23 5.1.4 SHELDUCKS ...... 28 5.1.5 WIGEON ...... 31 5.1.6 MALLARD ...... 34 5.1.7 COMMON EIDERS ...... 37 5.1.8 LONG-TAILED DUCKS ...... 42 5.1.9 COMMON SCOTER ...... 46 5.1.10 GOLDENEYE ...... 48 5.1.11 RED-BREASTED MERGANSERS ...... 51 5.1.12 TOTAL DIVERS ...... 54 5.1.13 RED-THROATED DIVERS ...... 59 5.1.14 BLACK-THROATED DIVERS ...... 62 5.1.15 GREAT-NORTHERN DIVERS ...... 64 5.1.16 FULMARS ...... 68 5.1.17 GANNETS ...... 73 5.1.18 TOTAL CORMORANTS & SHAGS ...... 78 5.1.19 CORMORANTS ...... 83 5.1.20 SHAGS ...... 86 5.1.21 GREY HERONS ...... 90 5.1.22 TOTAL GREBES ...... 93 5.1.23 SLAVONIAN GREBES ...... 96 5.1.24 TOTAL WADERS ...... 99 5.1.25 OYSTERCATCHERS ...... 104 5.1.26 LAPWINGS ...... 108 5.1.27 CURLEWS ...... 111 5.1.28 TOTAL SKUAS ...... 115 5.1.29 ARCTIC SKUAS ...... 118 5.1.30 GREAT SKUAS ...... 120 5.1.31 TOTAL SMALL GULLS...... 123 5.1.32 KITTIWAKES ...... 128 5.1.33 BLACK-HEADED GULLS ...... 133 5.1.34 COMMON GULLS ...... 137 5.1.35 TOTAL LARGE GULLS ...... 141

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5.1.36 LESSER BLACK-BACKED GULLS ...... 146 5.1.37 HERRING GULLS ...... 150 5.1.38 GREAT BLACK-BACKED GULLS ...... 154 5.1.39 TOTAL TERNS ...... 158 5.1.40 ARCTIC TERNS ...... 161 5.1.41 COMMIC TERNS ...... 163 5.1.42 TOTAL AUKS ...... 165 5.1.43 TOTAL COMMON GUILLEMOTS AND RAZORBILLS ...... 170 5.1.44 COMMON GUILLEMOTS ...... 175 5.1.45 RAZORBILLS ...... 179 5.1.46 BLACK GUILLEMOTS ...... 183 5.1.47 PUFFINS ...... 187 5.2 ABUNDANCE ESTIMATES AND DISTRIBUTION OF MARINE MAMMAL SPECIES / GROUPS ...... 190 5.2.1 TOTAL PHOCIDS ...... 190 5.2.2 COMMON SEALS ...... 194 5.2.3 GREY SEALS ...... 196 5.2.4 TOTAL DOLPHINS AND PORPOISES ...... 200 5.2.5 HARBOUR PORPOISES ...... 204 5.2.6 COMMON DOLPHINS ...... 206 5.2.7 WHITE-BEAKED DOLPHINS ...... 208 5.2.8 MINKE WHALES ...... 210 5.3 NUMBERS RECORDED AND DISTRIBUTION OF FISH ...... 212 5.4 COMPARISON OF YEAR 1 (2010 / 11) AND YEAR 2 (2012 / 13) AERIAL SURVEYS ...... 214 6 DISCUSSION ...... 217

6.1 SURVEY SUMMARY ...... 217 6.2 SECOND YEAR SPECIES ACCOUNTS ...... 217 6.2.1 WILDFOWL ...... 218 6.2.2 DIVERS ...... 220 6.2.3 FULMARS ...... 220 6.2.4 GANNETS AND CORMORANTS / SHAGS ...... 221 6.2.5 GREY HERON ...... 222 6.2.6 GREBES ...... 222 6.2.7 WADERS ...... 222 6.2.8 SKUAS ...... 222 6.2.9 GULLS ...... 223 6.2.10 TERNS ...... 224 6.2.11 AUKS ...... 224 6.3 MARINE MAMMALS ...... 225 6.3.1 PHOCIDS ...... 225 6.3.2 CETACEANS ...... 225 6.4 COMPARISON OF YEAR 1 (2010 / 11) AND YEAR 2 (2012 / 13) AERIAL SURVEYS ...... 225 6.5 FURTHER DATA ANALYSIS ...... 227 7 CONCLUSIONS ...... 228 8 REFERENCES ...... 230 9 APPENDIX I – JNCC BIRD GROUPS ...... 237 10 APPENDIX II – LATIN NAMES OF SPECIES RECORDED ...... 239 11 APPENDIX III – QA RESULTS ...... 240 12 APPENDIX IV – AVALABILITY BIAS CORRECTION FACTORS FOR DIVING SHAGS 243

iv APEM Final Report 511639

EXECUTIVE SUMMARY

1. This final report summarises results of all aerial surveys carried out in the Pentland Firth & Orkney Waters (PFOW) area during the second year.

2. Seven surveys were carried out between March 2012 and January 2013. These surveys were designed to characterise sea space usage by birds and marine mammals; birds on or over land were therefore not included.

3. The second year surveys used a stratified survey design; coverage of the survey area was more intensive within 3 km of land (‘near shore area’; images were taken every 500 m along transects spaced 2 km apart), compared to the rest of the PFOW survey area (‘wider area’; images were taken on a 2 km grid).

4. High Resolution digital images over water were analysed, covering 5,935 km2 of sea surface during each survey window.

5. Abundance estimates presented for all species are relative; birds and mammals under water at the time of survey were not accounted for. An example of how to calculate absolute abundance using an availability bias correction factor is presented in Appendix IV for shags.

6. Images were analysed and results for birds and marine mammals were Quality Assured by external experts. All data passed the agreement criteria.

7. For each survey window, abundance estimates for species / species groups were produced using design-based methods and distributions were displayed using relative density maps.

8. Fulmars were the most abundant bird species in the PFOW area. Peak abundance was recorded in December 2012 / January 2013 at an estimated 53,384 (42,282 – 64,486) birds.

9. Overall, birds were distributed throughout the PFOW area. Higher numbers of all bird species were recorded within the high coverage near shore area compared to the lower coverage wider area.

10. Phocids (seals) were the most abundant marine mammal group in the PFOW area with peak abundance recorded in October / November 2012 at an estimated 31,246 (11,240 – 51,251) seals. The majority (92%) of these seals were identified as grey seals.

11. To investigate whether there was any advantage to increasing survey coverage in the second year, first and second year data were compared.

12. Analysis of additional images collected concurrently during the second year surveys would increase the likelihood that model-based population estimates could be produced for individual species.

v APEM Final Report 511639

1. ABBREVIATIONS

GAM Generalised Additive Model JNCC Joint Nature Conservation Committee MS Marine Scotland PFOW Pentland Firth and Orkney Waters SAC Special Area of Conservation SPA Special Protection Area

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2. INTRODUCTION

APEM completed the second year of digital aerial surveys in the Pentland Firth and Orkney Waters (PFOW) area between March 2012 and January 2013 (Figure 2.1). This final report outlines results from all seven surveys undertaken during this timeframe.

All aerial survey work in the PFOW area has been jointly funded by Marine Scotland (MS) and The Crown Estate. The PFOW area has been identified as the location of some of the best marine energy (tidal stream and wave) resources in Scotland. The importance that the First Minister has placed on marine renewables and the development potential that exists in this location led to the Scottish Government agreeing to develop a marine plan for the PFOW. In 2008, The Crown Estate announced the first round for wave and tidal energy projects in PFOW. Following the competitive leasing round, The Crown Estate entered into leasing agreements for projects in PFOW with a potential capacity of up to 1,600 MW.

The PFOW area is also significant for a wide range of bird species, both in the breeding season and at other times of year. To ensure the conservation of a variety of bird species, a range of Special Protection Areas (SPAs) have been established under the Birds Directive (consolidated as Directive 2009/147/EC). Within the PFOW area, SPAs include sea cliff breeding sites bordering the Pentland Firth as well as other locations within the Orkney Islands archipelago. Based on recommendations from the Joint Nature Conservation Committee (JNCC; McSorley et al. 2003), Scottish ministers have recently approved seaward extensions to a number of the existing SPAs to protect adjacent marine habitats which are important for seabird resting and maintenance behaviour.

Aerial surveys have the advantage of covering a large area in a short space of time. APEM’s aerial surveys use state of the art camera technology to provide high resolution digital still images, collected from survey aircraft, in order to generate suitably robust data. APEM carried out the first year of aerial survey work in the PFOW area between November 2010 and August 2011. The methodology for these first year surveys used a 2 km grid survey design in which an image was analysed every 2 km along transects spaced 2 km apart over the entire area. The results of these surveys are detailed in APEM 2013a. At the request of The Crown Estate, additional images that were collected concurrently during the first year surveys were analysed and modelled abundance estimates, together with smoothed density surface maps of distribution, were presented in a further report on the first year data (APEM 2013b).

An evolved survey design was used in the second year. Instead of a 2 km grid design over the entire area, a stratified survey design was used with higher survey effort within 3 km of land (‘near shore area’) compared to the rest of the survey area (‘wider area’). In the near shore area images were taken every 500 m along transects spaced 2 km apart, and in the wider area images were taken every 2 km along transects spaced 2 km apart. The aim of this revised survey design was to make better use of survey effort by focussing coverage in areas of high interest. As many bird species (e.g. auks, waders, wildfowl) often utilise near shore areas of sea more heavily than offshore areas, these modified surveys were undertaken to increase the number of species and individuals recorded.

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Figure 2.1: The Pentland Firth and Orkney Waters area with Special Protection Areas.

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3. AIMS & OBJECTIVES

The aim of this final report is to describe the data collected during all seven aerial surveys in the second year between March 2012 and January 2013.

Design-based abundance estimates of birds at sea and marine mammals (with confidence limits and associated precision) were calculated for individual species and species groups. The design-based method is based on first ecological principles, whereby a systematic sample describes the variation in abundance and distribution across a survey area. These abundance estimates were relative, as birds and mammals under water at the time of the survey were not accounted for using availability bias correction factors (but see Appendix IV). Relative abundance estimates were calculated for three areas of the PFOW including 1) the ‘near shore area’ which was the area within a 3 km boundary surrounding the land (images were collected every 500 m), 2) the ‘wider area’ which was the area between the 3 km land boundary and the outer boundary of the PFOW area (images were collected every 2 km) and 3) the entire PFOW area. Distributions of birds and marine mammals were displayed on relative density maps comprising points for each individual animal sighted.

In addition, this final report also provides a short comparison between the first year (uniform 2 km grid design) and second year (stratified survey design) data to investigate whether increasing the survey coverage within the first 3 km of land improved the data set.

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4. METHODS

4.1. Survey outline

Aerial surveys were undertaken using Britten-Norman Islander and Vulcanair P68 Observer twin engine survey aircraft. Surveys involved digital still image collection using a GPS- linked bespoke flight management system and were flown at an average altitude of approximately 890 feet to avoid flushing birds (consistent with COWRIE recommendations, Thaxter & Burton 2009).

From the images collected, bird and marine mammal abundance estimates and distributions were derived using design-based methods. Only at sea encounters for birds were considered for analysis. The methodology used to estimate abundance at sea was consistent with that used for the first year aerial survey data (APEM 2013a). For all species, relative at sea estimates were produced which did not account for animals under water. An example of how to calculate absolute abundance using an availability bias correction factor is presented in Appendix IV for shags. As bird occurrence and distribution at sea is relatively unknown compared with birds on land, the focus of the PFOW aerial surveys was to count birds at sea. Therefore, bird records on or over land were not included. When an area of sea and land was captured within one image, birds on or over the water were counted while those on or over the land were not.

To estimate seal populations, seals at haul out sites on land (always within a few metres of the water edge) were included in the analysis; otherwise all marine mammals included in the analysis were recorded at sea. Each bird (or marine mammal) captured in an image was geo- referenced allowing the spatial locations of animals to be accurately mapped. Population estimates were derived with a given level of precision.

4.2. Survey timings

Seven surveys of the PFOW area were carried out between March 2012 and January 2013. Survey timings were proposed by WWT Consulting which conformed to the principles laid out in the Joint Agency Guidance (Defra 2005). The Joint Agency Guidance aims to provide (where possible) coverage during periods of key ornithological interest in UK waters. Development in offshore areas has the potential to affect birds throughout the year. Large numbers of seabirds congregate in offshore areas during the winter period, often in high concentrations. The spring and early summer periods are also important, especially in those areas adjacent to breeding seabird colonies. Finally, post-breeding season flocks, moulting seaducks and migrating birds are also vulnerable, up to and including spring migration. Survey windows were designed to encompass this biological variability across non-breeding and breeding seasons for birds, and are shown in Table 4.1 below.

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Table 4.1: Survey windows and survey dates for Pentland Firth and Orkney Waters surveys.

Survey window Actual survey dates Survey 1 1 February – 31 March 2012 1 – 5 March 2012 Survey 2 1 April – 15 May 2012 13 – 15 April 2012 Survey 3 16 May – 26 June 2012 16 – 17 May 2012 Survey 4 27 June – 7 August 2012 20 – 21 July 2012 Survey 5 8 August – 18 September 2012 9 – 12 August 2012 Survey 6 24 October – 30 November 2012 3 – 4 November 2012 Survey 7 1 December 2012 – 31 January 2013 12, 13 and 15 January 2013

4.3. Survey design

Figure 4.1 shows a schematic plan of the survey design. Within a 3 km boundary surrounding the land (near shore area), images were taken every 500 m along transect lines spaced 2 km apart. Beyond the 3 km land boundary (wider area), images were taken every 2 km along transect lines spaced 2 km apart up to the boundary of the PFOW area. Each black point on Figure 4.1 represents an image collected during a survey. To ensure a random sampling of imagery, transects were offset by approximately 285 m for each survey, i.e. the first transect flown on one survey was 285 m away from the first transect on another survey. Flight lines were orientated in a north-south direction across the entire survey area using flight planning software. The total survey area represents approximately 5,935 km2 over the sea surface (6,900 km2 if including area over land).

4.4. Survey coverage

A total of 21,681 images were analysed from seven surveys in the PFOW area comprising a total of 13,985 images collected in the near shore area and 7,696 images collected in the wider area. These images or ‘samples’ provided enough data for robust statistical analysis. The number of images analysed per survey, the survey area and survey coverage are summarised in Table 4.2. Images were collected at a 3 cm Ground Surface Distance (GSD) resolution, consistent with accepted guidelines (Thaxter & Burton 2009).

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Figure 4.1: Survey design in the PFOW study area.

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Table 4.2: Coverage of the survey area

Number of Survey area Survey

images (km2) coverage (%) NSA (500 m) survey 1 1,961 89.33 1.50 WA (2 km) survey 1 1,099 47.32 0.80 Total Survey 1 3,060 136.65 2.30 NSA (500 m) survey 2 1,926 92.41 1.56 WA (2 km) survey 2 1,095 52.17 0.88 Total Survey 2 3,021 144.58 2.44 NSA (500 m) survey 3 1,904 85.00 1.43 WA (2 km) survey 3 1,103 44.05 0.74 Total Survey 3 3,007 129.05 2.17

NSA (500 m) survey 4 1,934 73.54 1.24 WA (2 km) survey 4 1,108 47.32 0.80 Total Survey 4 3,042 120.87 2.04

NSA (500 m) survey 5 1,890 58.32 0.98 WA (2 km) survey 5 1,090 36.68 0.62 Total Survey 5 2,980 95.00 1.60

NSA (500 m) survey 6 2,185 83.00 1.40 WA (2 km) survey 6 1,114 48.00 0.81 Total Survey 6 3,299 131.00 2.21

NSA (500 m) survey 7 2,185 94.94 1.60 WA (2 km) survey 7 1,087 39.62 0.67 Total Survey 7 3,272 134.57 2.27 NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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4.5. Data processing and Quality Assurance

The following data were recorded:

 bird / mammal species code, group and English name;  behaviour (sitting on water or flying over water);  count (number of individuals);  position (easting, northing) of individuals;  date and time stamp of image collection.

Bird and mammal species were identified, where possible, to species level. Where bird identification was not possible to species, groups consistent with JNCC protocol were used (see Appendix 1).

Both internal and external Quality Assurance (QA) was carried out on each survey. Images were assessed in batches with a different staff member responsible for each batch.

Images containing no birds (‘blank’ images) were removed and kept separately for further QA. Of these blank images, 10% were randomly selected for QA by an independent reviewer. If there was less than 90% agreement, the entire batch of images was re-analysed.

All images containing birds were analysed and then checked by APEM’s own dedicated QA Manager, ensuring that 100% of all birds detected in images were subject to internal QA. The QA manager, an experienced ornithologist, is responsible for maintaining and updating the image library and also provides advice and guidance to the image processing staff.

Upon completion of the internal QA, 10% of the birds located in each survey were subject to external QA by an independent organisation. The appointed auditors for seabirds are the British Trust for Ornithology (BTO). The images for external QA were selected at random using a random number generator. The selected images were provided to the BTO along with information on measured body lengths and wingspans of the birds. All identifications were conducted ‘blind’ by the external analyst. Upon completion, a confusion matrix was created to show the proportion of agreement and identify areas of potential misidentification. It was established at the start of the project that at least a 90% agreement between BTO and APEM would be required and that any disagreements would be reviewed. It was also established that if the 90% threshold was not reached then a further 10% of images would be assessed by the BTO and that if the 90% agreement was still not achieved after secondary assessment, then the entire batch of images would be required to be reassessed and the QA process repeated. However, the results in Table 4.3 show that a very high agreement (>96% for all surveys) between BTO and APEM was reached and therefore secondary assessment was not necessary. Further details of the QA for individual species in each survey are presented in Appendix III.

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Table 4.3: QA results for all 2012 / 13 PFOW surveys

Survey Number of Overall percentage birds recorded agreement Survey 1 1 February – 31 March 2012 4,106 98.8 Survey 2 1 April – 15 May 2012 1,881 99.5 Survey 3 16 May – 26 June 2012 2,712 96.7 Survey 4 27 June – 7 August 2012 2,522 96.5 Survey 5 8 August – 18 September 2012 1,204 97.6 Survey 6 24 October – 30 November 2012 3,333 97.6 Survey 7 1 December 2012 – 31 January 2013 4,772 98.5

For marine mammals, all images containing such animals were analysed, put through internal QA and 100% were then sent for external QA. The appointed auditors for marine mammals are SMRU Ltd. Upon return of their identifications, the data were updated accordingly with any improvements on the level of identification already achieved by the image analysts and ornithologists.

4.6. Data analysis

4.6.1 Design-based abundance estimates

Design-based estimates of bird and marine mammal abundance with confidence limits (CL) and associated precision of estimates were calculated for the different areas within the stratified sampling design including 1) near shore area, 2) wider area and 3) the total PFOW area.

Abundance estimates calculated in this report are relative and do not account for birds or mammals under water at the time of survey. Therefore, diving bird species and marine mammals are likely to have been underestimated in this report. To calculate absolute abundance estimates, species specific correction factors should be applied; an example of how to do this for shags is provided in Appendix IV.

Raw counts were extracted from geo-referenced images, with birds falling outside the survey area or over land excluded from calculations. Where an image fell across the survey boundary, only the part of the image that fell within the survey area was included in the analysis.

All analysis and data manipulation were conducted in the R programming language (R Development Core Team 2010) and non-parametric 95% confidence intervals were generated using the ‘boot’ library of functions (Canty & Ripley 2010).

4.6.1.1 Abundance estimates

To calculate population estimates, it is necessary to know the total number of images required to cover the survey area. This was done by calculating the average size of an image footprint. An average image footprint was calculated by dividing the sum of the image areas contained within the survey area by the number of images that were wholly or partially within the 9

APEM Final Report 511639 survey area. The mean footprint size across all seven surveys presented in this report was 41,126 m2. The total number of images required to cover the study area was then calculated, excluding land.

Relative population estimates for the near shore and wider area strata were generated by adding up the raw counts from geo-referenced images and dividing this number by the total number of images to give the mean number of birds per image (i). Relative population estimates (N) for each survey month were then calculated by multiplying the mean number of birds per image by the total number of images required to cover the entire study area (A). This is analogous to abundance estimation outlined in Borchers et al. (2002).

N = i A

To produce a relative population estimate for the total PFOW area (Nstatified), estimates from the near shore and wider area strata were combined using the following stratified sampling analysis technique (Thompson 2012).

Nstatified = ∑ Ahih

Where Ah is the total number of images required to cover the entire study area within stratum h and ih is the mean number of birds per image within stratum h.

4.6.1.2 Confidence limits

For the near shore and wider area relative population estimates, confidence limits (CL) showing the extent of variability surrounding the relative population estimate were calculated using a non-parametric bootstrap method. APEM routinely use bootstrap methods to calculate CL as this statistical method is considered to be a very robust way of assigning measures of accuracy (Borchers et al. 2002). For the bootstrap simulation, a sub-sample of images within stratums were re-sampled 999 times with replacement from image data (i.e. 999 subsamples of the raw counts were used to produce 999 new ‘total raw count’ values). Each of the 999 bootstrap values were then used to produce relative population estimates within each stratum as described in section 4.6.1.1. The upper and lower 95% confidence intervals (+CL and –CL respectively) of all the bootstrapped population estimates was taken as the variability of the statistic over the population (Efron & Tibshirani 1993).

To calculate confidence intervals for the total PFOW relative population estimate, the unbiased estimate of variance of the mean was first calculated (Thompson 2012).

2 2 Vâr(istratified) = ∑(Ah/A) ((Ah-ah)/Ah)(s h/ah)

Where Ah is the total number of images required to cover the entire study area within stratum h, A is the total number of images required to cover the entire study area, ah is the number of 2 images collected within stratum h, and s h is the sample variance within stratum h.

An approximate 100(1-α)% confidence interval for the population total can be calculated when stratum sample sizes are sufficiently large (if all stratum samples sizes are greater than 30).

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4.6.1.3 Precision

For every population estimate, APEM calculates a CV’ (coefficient of variation) to provide a measure of precision about the mean population estimate, i.e. to provide a measure of how good the estimates are of the relative population. As aerial survey grid data normally contains a high proportion of images with zero counts (as animals are not normally evenly distributed across the survey area), measures of precision were calculated from the raw count data using a negative binomial estimator which is suitable for a pseudo-Poisson over dispersed distribution data caused by zero counts (Elliott 1977). This produced a CV’ based on the relationship of the standard error (SE) to the mean (μ).

CV’ = SE / μ

Effectively, this statistic is used to determine whether the sampling regime is sufficient to estimate the population with a given level of precision. A CV’ ≤ 0.16 relates to a precision level able to detect a doubling or halving of the population (Bohlin, 1990), although at very low densities, it is not always mathematically possible to obtain a CV’ of 0.16, even if 99% of the area is covered.

4.6.2 Relative density distribution maps

Bird observations were comprised of individual points for each bird sighted, geo-referenced to actual spatial location at the time of sighting. ArcGIS (version 9.2) software was used to consolidate data for mapping by summarising each bird location by centroid of the image in which it was recorded. A buffer was added to surveyed image centroids for each month using the Proximity-Buffer tool in ArcToolbox. These data were overlain with the bird observation data for each of the major group of birds (auks, large gulls, etc.) for each month of survey using the Overlay-Spatial Join tool in ArcToolbox. This provided a total count of birds at each grid point.

These spatially-joined files were imported into ArcGIS and used to produce relative density maps giving varying sized points relative to the number of bird records at each image location.

4.7. Weather conditions

A breakdown of the weather conditions on each survey, and any other significant information from survey notes, is shown below (Table 4.3). The weather is described for all transects surveyed in the morning and / or the afternoon on each survey day.

APEM uses the World Meteorological Organization (WMO) sea state chart to record sea state; the cut off point for APEM’s surveys is above sea state 5. The ease with which birds and mammals can be detected in higher sea states depends to some degree on the swell frequency. It is possible to have a sea state 5 with low swell frequency, as was the case during a part of surveys 2 and 7. Birds are less likely to be missed in a low swell frequency than in a high swell frequency at the same sea state. All surveys were conducted during the best available weather conditions in each survey window; during the winter months the

APEM Final Report 511639 choice of ideal weather conditions to conduct the survey over consecutive days was generally reduced. If weather conditions deteriorated to such an extent during a survey where it was likely that birds could be missed in the images, the survey was either cancelled or stopped temporarily until the weather conditions became suitable for survey once again.

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Table 4.3: Survey dates and weather conditions.

Date surveys Time of Wind speed / State of seas Visibility Other significant information undertaken Day direction March 1st PM 1 to 2 18 knots / N >10 km March 2nd PM 3 15 knots / N >10 km Good bright day, turning hazy at the end AM 3 20 – 25 knots / SE >10 km March 3rd 1 PM 3 20 – 25 knots / SE >10 km Few clouds, good bright conditions AM 2 10 – 15 knots / SW >10 km March 4th PM 2 10 – 15 knots / SW >10 km March 5th PM 2 to 3 12 knots / NW >10 km April 13th PM 3 to 4 20 – 30 knots / N >10 km AM 3 to 4 20 – 30 knots / N 8 - 10 km Scattered heavy showers reducing visibility April 14th 2 PM 5 25 knots/ N >10 km AM 4 14 knots / NNW >10 km April 15th PM 4 12 knots / NNW >10 km May 16th PM 3 to 4 10 – 15 knots / S >10 km 3 AM 1 to 4 10-20 knots / SW >10 km Bright conditions May 17th PM 1 to 4 10-20 knots / SW >10 km Rain showers AM 3 10 – 15 knots / W >10 km Overcast but good light July 20th PM 3 10 – 15 knots / W >10 km Overcast but good light 4 AM 1 – 3 20 – 30 knots / W >10 km Overcast July 21st PM 2 – 4 20 – 30 knots / W >10 km Bright good conditions

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Date surveys Time of Day State of seas Wind speed / direction Visibility Other significant information undertaken August 9th PM 1 to 2 9 - 16 knots / W >10 km Excellent visibility > 60 km August 10th AM 1 to 2 7 knots SSW >10 km 5 AM 2 7 knots / S >10 km August 11th PM 2 to 3 17 knots /SE >10km Clear skies August 12th AM 2 15 knots / SE >10 km Overcast AM 3 20 knots / WSW >10 km November 3rd 6 PM 2 to 3 22 knots / S >10 km November 4th AM 3 18 knots / SE >10 km January 12th AM 4 to 5 13 to 20 knots / SSW Variable <5 km to >10 km Winds gusting to 30 knots 7 January 13th AM 5 15 knots / S >10 km January 15th AM 2 to 3 5 knots / SSE >10 km

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5 RESULTS

5.1 Abundance estimates and distribution of bird species / groups

All bird abundance estimates presented in the following tables in the results section are relative, as they do not account for birds under water at the time of the survey.

5.1.1 Mute swans

5.1.1.1 Abundance estimates

Data presented in Table 5.1 refer to mute swans. Small numbers of mute swans were recorded during the May / June, June / August and October / November 2012 survey windows. The relative peak population recorded in June / August 2012 was estimated at 73 (3 – 213) individuals. All mute swans were recorded within the near shore area.

Table 5.1: Raw counts, number of sightings, population estimates, confidence limits and precision for mute swans in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 2 3 0 1 0 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 0 2 3 0 1 0 NSA (500 m) 0 0 1 1 0 1 0 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 0 0 1 1 0 1 0 NSA (500 m) 0 0 42 73 0 22 0 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 0 42 73 0 22 0 NSA (500 m) 0 0 2 3 0 1 0 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 2 3 0 1 0 NSA (500 m) 0 0 127 219 0 65 0 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 123 213 0 63 0 NSA (500 m) N/A N/A 0.71 0.58 N/A >1 N/A Precision WA (2 km) N/A N/A N/A N/A N/A 0 N/A Total N/A N/A 0.15 0.12 N/A 0.22 N/A Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.2 : Behaviour (sitting or flying) of mute swans in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar20 May Jun Aug /Sep Nov Jan 12 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 2 3 0 1 0 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 0 0 0 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.1.2 Distribution

During the May / June 2012 survey window, two mute swans were recorded together < 1 km from shore in the Bay of Firth on the north side of the Orkney Mainland (Figure 5.1: A).

In June / August 2012, three mute swans were recorded in three separate locations. Two mute swans were recorded close to the coast off South Ronaldsay, one on the west side and the other on the east side of the island. The third swan was located close to Taracliff Bay on the south-east side of the Orkney Mainland (Figure 5.1: B).

In October / November 2012, one mute swan was recorded close to the coast on the north side of Wyre (Figure 5.1: C).

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Figure 5.1: Distribution of mute swans recorded in the PFOW area in May / June, June / August and October / November 2012 survey windows (there are no maps for windows where no birds were recorded).

A: May / June 2012 B: June /August 2012

C: October / November 2012

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5.1.2 Greylag geese

5.1.2.1 Abundance estimates

Data presented in Table 5.3 refer to greylag geese. Low to moderate numbers of greylag geese were recorded in all survey windows. The relative peak population recorded in October / November 2012 was estimated at 9,007 (417 – 17,838) individuals. All greylag geese were recorded within the near shore area.

Table 5.3: Raw counts, number of sightings, population estimates, confidence limits and precision for greylag geese in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 122 34 8 168 25 417 353 Count WA (2 km) 0 0 0 0 0 0 0 Total 122 34 8 168 25 417 353 NSA (500 m) 9 7 2 7 3 7 15 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 9 7 2 7 3 7 15 NSA (500 m) 2,448 660 169 4,095 768 9,007 6,665 Population WA (2 km) 0 0 0 0 0 0 0 Total 2,448 660 169 4,095 768 9,007 6,665 NSA (500 m) 662 78 8 171 25 1,620 1,529 LCL WA (2 km) 0 0 0 0 0 0 0 Total 377 34 8 168 25 417 353 NSA (500 m) 4,796 1,668 506 11,969 2,275 19,699 14,274 UCL WA (2 km) 0 0 0 0 0 0 0 Total 4,519 1,533 424 9,722 2,027 17,838 13,459 NSA (500 m) 0.09 0.17 0.35 0.08 0.2 0.05 0.05 Precision WA (2 km) N/A N/A N/A N/A N/A N/A 0 Total 0.02 0.04 0.08 0.02 0.04 0.01 0.01 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.4 : Behaviour (sitting or flying) of greylag geese in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar20 May Jun Aug /Sep Nov Jan 12 2012 2012 2012 2012 2012 2013 NSA (500 m) 112 0 6 49 0 0 52 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 10 34 2 119 25 417 301 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.2.2 Distribution

In February / March 2012, greylag geese were recorded in several groups < 1 km from shore in different locations around the Orkney Isles (Figure 5.2: A). A large group (+ 30 birds) was recorded on Graemsay Island between Hoy and the Orkney Mainland, and further large groups (11 – 30 birds) were recorded from Papa Westray in the north to Hunda island in the south. Large groups were also recorded just off the north coast of the Orkney Mainland and off the east side of the isle of Burray (Figure 5.2: A).

In April / May 2012, the majority of greylag geese were located in a large group (11 – 30 birds) off the south end of Egilsay and another group was located in the Bay of Sandoyne off the south-eastern side of the Orkney Mainland (Figure 5.2:B).

During the May / June 2012 survey window, greylag geese were grouped together in the Bay of Isbister on the north-east coast of the Orkney Mainland and off the northern point of the isle of Fara (Figure 5.2:C).

In June / August 2012, the majority of greylag geese were located in two large groups close together in Rousay Sound next to the isle of Rousay and the other off Egilsay, while smaller groups were located off the islands of Gairsay, Shapinsay and the south coast of the Orkney Mainland (Figure 5.2:D).

During the August / September 2012 survey window, greylag geese were located in two groups close to the shore; in Veantrow Bay along the northern coast of Shapinsay and off the north coast of Eday (Figure 5.2:E).

In October / November 2012, greylag geese were recorded in several groups in different locations around the Orkney Isles (Figure 5.2: F). Two large groups were recorded on Shapinsay; one group (11-30 birds) was recorded on the west coast near the Bay of Furrowend and one group (+31 birds) was recorded at the south-east point of Shapinsay near the Bay of Sandgarth. Two large groups (+ 31 birds) were observed along the east coast of the Orkney Mainland and a further large group (+31 birds) was recorded on the western tip of Fersness Bay along the coast of Eday. Smaller groups of individual greylag geese were recorded on the east coast of Eday and the south coast of Westray (Figure 5.2: F).

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In December 2012 / January 2013, large clusters (7 – 31 birds) were recorded along the north coast of Graemsay, south of Stromness near the Bay of Naverhaw on the Orkney Mainland and north of Costa and the Broch of Gurness also on the Orkney Mainland. Large groups were also located in Fersness Bay on the west coast of Eday and off the Berst Ness and Bow Head on Westray (Figure 5.2:G).

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Figure 5.2: Distribution of greylag geese recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.3 Total ducks

5.1.3.1 Abundance estimates

Data presented in Table 5.5 refer to total ducks (including shelducks, wigeon, mallards, common eiders, long-tailed ducks, goldeneyes, red-breasted mergansers and ducks not identified to species level). Low to moderate numbers of ducks were recorded in each survey window; the relative peak population was recorded in February / March 2012 at an estimated 15,031 (5,204 – 24,858) birds. The majority of ducks were recorded within the near shore area. The numbers of ducks identified to species level is presented in Table 5.7. Relative population estimates for ducks that could be identified to species are provided in subsequent sections.

Table 5.5: Raw counts, number of sightings, population estimates, confidence limits and precision for total ducks in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 749 221 49 68 84 647 594 Count WA (2 km) 0 0 0 0 0 3 1 Total 749 221 49 68 84 650 595 NSA (500 m) 66 23 29 7 9 117 78 Number of WA (2 km) 0 0 0 0 0 2 1 sighting Total 66 23 29 7 9 119 79 NSA (500 m) 15,031 4,287 1,033 1,658 2,582 13,975 11,216 Population WA (2 km) 0 0 0 0 0 259 105 Total 15,031 4,287 1,033 1,658 2,582 14,234 11,320 NSA (500 m) 7,084 1,552 591 122 799 9,677 6,155 LCL WA (2 km) 0 0 0 0 0 3 1 Total 5,204 845 585 68 582 9,704 5,801 NSA (500 m) 26,309 8,187 1,497 3,851 4,918 18,813 17,182 UCL WA (2 km) 0 0 0 0 0 777 314 Total 24,858 7,730 1,482 3,515 4,582 18,764 16,840 NSA (500 m) 0.04 0.07 0.14 0.12 0.11 0.04 0.04 Precision WA (2 km) N/A N/A N/A N/A N/A 0.58 >1 Total 0.01 0.02 0.03 0.02 0.02 0.01 0.01 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.6: Behaviour (sitting or flying) of total ducks geese in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 600 211 47 67 83 561 583 Sitting WA (2 km) 0 0 0 0 0 3 1 NSA (500 m) 149 10 2 1 1 86 11 Flying WA (2 km) 0 0 0 0 0 0 0

Table 5.7: Total number of each species of duck recorded.

Survey SU WN MA E. LN CX GN RM U window Feb / Mar 3 230 0 322 158 0 0 29 7 2012 Apr / May 0 20 0 197 1 0 2 0 1 2012 May / Jun 2 0 0 24 12 0 0 0 11 2012 Jun / Aug 0 0 0 68 0 0 0 0 0 2012 Aug / Sep 0 0 0 84 0 0 0 0 0 2012 Oct / Nov 0 115 35 292 58 45 37 28 40 2012 Dec 2012 / 2 120 160 152 23 0 20 7 111 Jan 2013 SU: Shelduck, WN: Wigeon, MA: Mallard, E.: Eider, LN: Long-tailed duck, CX: Common Scoter, GN: Goldeneye, RM: Red-breasted merganser, U: Unidentified duck

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5.1.3.2 Distribution

In February / March 2012, ducks were recorded close to shore in many groups around the Orkney Islands, Pentland Firth islands and off the north-east coast of the Scottish mainland (Figure 5.3: A). Ducks were recorded from the tip of Mull Head off Papa Westray in the north to Thurso Bay off the Scottish mainland in the south (Figure 5.3: A).

In April / May 2012, fewer ducks were recorded close to shore mostly around the Orkney Isles from Papa Westray in the north to South Walls in the South. Two small groups were also recorded off Brims Ness and Sandside Bay off the Scottish mainland. Some large groups were recorded around the Orkney Mainland, Rousay, Egilsay, Burray and Hoy (Figure 5.3: B).

During the May / June 2012 survey window, ducks were recorded close to land in many scattered small groups around the Orkney Isles and mainland Scotland from Westray in the north to Loch Eriboll off the Scottish mainland (Figure 5.3: C).

In June / August 2012 survey window, two large groups of ducks were located close to the coast of Westray and South Ronaldsay in the Orkney Islands and the island of Stroma in the Pentland Firth (Figure 5.3 D).

In August / September 2012 the majority of ducks were located in three large groups (11 – 30 birds) off the north coast of South Ronaldsay and in Echnaloch Bay (Figure 5.3:E). Further large groups (11 – 30 birds) were recorded on the north and south-east coast of the Orkney Mainland near the Bay of Carness and Dingyshowe Bay. Smaller groups (3 - 6 birds) were recorded along the east coast of Rousay and the west coast of South Ronaldsay (Figure 5.3: E).

During the October / November 2012 survey window ducks were recorded close to the shore in many groups around the Orkney and Pentland Firth Isles (Figure 5.3: F). Ducks were recorded from the northern tip of Papa Westray to the southern tip of South Ronaldsay with the majority of birds recorded along the northern coast of the Orkney Mainland (Figure 5.3: F).

In December 2012 / January 2013, ducks were recorded close to shore in many groups around the Orkney Islands, Pentland Firth islands and off the north-east coast of the Scottish mainland (Figure 5.3: A). Ducks were recorded from the tip of Bow Head off Westray to the north of Fraserburgh off the Scottish Mainland (Figure 5.3: G).

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Figure 5.3: Distribution of total ducks recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012 26

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.4 Shelducks

5.1.4.1 Abundance estimates

Data presented in Table 5.8 refer to shelducks. Small numbers of shelducks were recorded in the February / March 2012, May / June 2012 and December 2012 / January 2013 surveys. Numbers peaked in February / March 2012 when the relative population was estimated at 60 (3 – 175) birds. All shelducks were recorded within the near shore area.

Table 5.8: Raw counts, number of sightings, population estimates, confidence limits and precision for shelducks in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 3 0 2 0 0 0 2 Count WA (2 km) 0 0 0 0 0 0 0 Total 3 0 2 0 0 0 2 NSA (500 m) 1 0 1 0 0 0 1 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 1 0 1 0 0 0 1 NSA (500 m) 60 0 42 0 0 0 38 Population WA (2 km) 0 0 0 0 0 0 0 Total 60 0 42 0 0 0 38 NSA (500 m) 3 0 2 0 0 0 2 LCL WA (2 km) 0 0 0 0 0 0 0 Total 3 0 2 0 0 0 2 NSA (500 m) 181 0 127 0 0 0 113 UCL WA (2 km) 0 0 0 0 0 0 0 Total 175 0 123 0 0 0 110 NSA (500 m) 0.58 N/A 0.71 N/A N/A N/A 0.71 Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total 0.13 N/A 0.15 N/A N/A N/A 0.16 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.9: Behaviour (sitting or flying) of shelducks in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 2 0 0 0 2 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 3 0 0 0 0 0 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.4.2 Distribution

In February / March 2012 survey window, all three shelducks were recorded in a cluster in the Bay of Ireland situated within 1 km off the south-west coast of the Orkney Mainland (Figure 5.4: A).

In May / June 2012 survey window, two shelducks were recorded within the sea loch of Loch Eriboll on the north-west coast of mainland Scotland (Figure 5.4: B).

During the December 2012 / January 2013 survey window, two shelducks were recorded in the Bay of Stove on Sanday on the east Pentland Firth Survey Area boundary (Figure 5.4:C).

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Figure 5.4: Distribution of shelducks recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: May / June 2012

C: December 2012 / January 2013 30

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5.1.5 Wigeon

5.1.5.1 Abundance estimates

Data presented in Table 5.10 refer to wigeon. Small to moderate numbers of wigeon were recorded in February / March 2012, April / May 2012 and October / November 2012 survey windows. Numbers peaked in February / March 2012 when the relative population was estimated at 4,616 (875 – 8,357) birds. All wigeon were recorded within the near shore area.

Table 5.10: Raw counts, number of sightings, population estimates, confidence limits and precision for wigeon in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 230 20 0 0 0 115 120 Count WA (2 km) 0 0 0 0 0 0 0 Total 230 20 0 0 0 115 120 NSA (500 m) 15 3 0 0 0 6 9 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 15 3 0 0 0 6 9 NSA (500 m) 4,616 388 0 0 0 2,484 2,266 Population WA (2 km) 0 0 0 0 0 0 0 Total 4,616 388 0 0 0 2,484 2,266 NSA (500 m) 1,264 20 0 0 0 497 208 LCL WA (2 km) 0 0 0 0 0 0 0 Total 875 20 0 0 0 115 120 NSA (500 m) 8,970 1,009 0 0 0 5,616 6,193 UCL WA (2 km) 0 0 0 0 0 0 0 Total 8,357 869 0 0 0 4,970 5,575 NSA (500 m) 0.07 0.22 N/A N/A N/A 0.09 0.09 Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total 0.01 0.05 N/A N/A N/A 0.02 0.02 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.11: Behaviour (sitting or flying) of wigeon in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 93 12 0 0 0 42 109 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 137 8 0 0 0 73 11 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.5.2 Distribution

In February / March 2012, three large groups of wigeon (>31 birds) were recorded in three separate locations around the Orkney Mainland including the Bay of Ireland, Bay of Firth and Deer Sound. A further couple of large groups of wigeon (11 – 30 birds) were recorded close to land in the north of the study area in Papa Sound and in the Bay of Cubbigo off Westray. Smaller groups of wigeon were recorded close to shore scattered throughout the Orkney Isles including Rousay Sound and Wyre Skerries around Rousay, The String off the north coast Mainland Orkney, Burray Ness and Hunda Sound off Burray and Pan Hope off Flotta (Figure 5.5: A).

During the April / May 2012 survey window, smaller numbers of wigeon were recorded in The String and Bay of Berstane off the north coast of Mainland Orkney and off Burray Ness around the island of Burray (Figure 5.5: B).

In October / November 2012, two large groups (11 – 31 birds) were recorded in Widewall Bay to the west of South Ronaldsay, a further large group and two smaller groups of wigeon were observed along the northern coast of Orkney Mainland and one large group (11-30 birds) was also recorded in the Bay of Brough on the north coast of Westray (Figure 5.5: C)

During the December 2012 / January 2013 survey window, a large group of wigeon ( + 31 birds) was observed on the north tip of Orkney Island near the Bay of Roeness, with smaller clusters recorded south of Tankerness and in the Bay of Ireland off the Orkney Mainland and in North Bay south of Hoy . Individuals were also observed close to the coasts of South Ronaldsay and Flotta (Figure 5.5:D).

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Figure 5.5: Distribution of wigeon recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: October / November 2012 D: December 2012 / January 2013 33

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5.1.6 Mallard

5.1.6.1 Abundance estimates

Data presented in Table 5.12 refer to mallards. Small numbers of mallards were recorded in the October / November 2012 and December 2012 / January 2013 survey windows, the relative peak population recorded in the last survey window was estimated at 3,021 (160 – 6,268) birds. All mallards were recorded within the near shore area.

Table 5.12: Raw counts, number of sightings, population estimates, confidence limits and precision for mallard in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 33 160 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 33 160 NSA (500 m) 0 0 0 0 0 5 7 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 0 0 0 0 0 5 7 NSA (500 m) 0 0 0 0 0 713 3,021 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 713 3,021 NSA (500 m) 0 0 0 0 0 108 453 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 33 160 NSA (500 m) 0 0 0 0 0 1,447 6,778 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 1,393 6,268 NSA (500 m) N/A N/A N/A N/A N/A 0.17 0.08 Precision WA (2 km) N/A N/A N/A N/A N/A N/A 0 Total N/A N/A N/A N/A N/A 0.04 0.02 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.13: Behaviour (sitting or flying) of mallard in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 23 160 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 0 0 10 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.6.2 Distribution

In October / November 2012, two large groups of mallards (+ 30 birds) were recorded to the north-east of the Orkney Mainland. A further moderate group of mallards (7 – 10 birds) was recorded close to land in the north of the study area, in the Bay of Tuquoy off Westray. Two smaller groups were recorded on the east coast of South Ronaldsay, south west of Burray and in Widewall Bay (Figure 5.6: A).

During the December 2012 / January 2013 survey, large groups ( +31 birds) of mallards were observed north of Kinnaird Head off the Scottish Mainland and south of Spur Ness on Sanday on the eastern Pentland Firth Survey Area boundary (Figure 5.6:B). Groups of 11- 31 birds were recorded on the south coast of Flotta and on the east coast of South Ronaldsay, with pairs of mallards also observed south of Hoy in North Bay (Figure 5.6:B),

APEM Final Report 511639

Figure 5.6: Distribution of mallard recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: October / November 2012 B: December 2012 / January 2013

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5.1.7 Common eiders

5.1.7.1 Abundance estimates

Data presented in Table 5.14 refer to common eiders. Small numbers of common eiders were recorded in all survey windows. Numbers peaked in February / March 2012 when the relative population was estimated at 6,462 (500 – 12,424) birds. All common eiders were recorded within the near shore area.

Table 5.14: Raw counts, number of sightings, population estimates, confidence limits and precision for common eiders in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 322 197 24 68 84 289 152 Count WA (2 km) 0 0 0 0 0 3 0 Total 322 197 24 68 84 292 152 NSA (500 m) 38 18 12 7 9 78 37 Number of WA (2 km) 0 0 0 0 0 2 0 sightings Total 38 18 12 7 9 80 37 NSA (500 m) 6,462 3,822 506 1,658 2,582 6,242 2,870 Population WA (2 km) 0 0 0 0 0 259 0 Total 6,462 3,822 506 1,658 2,582 6,501 2,870 NSA (500 m) 2,268 1,106 190 146 799 4,169 1,737 LCL WA (2 km) 0 0 0 0 0 3 0 Total 500 415 164 68 582 4,353 1,593 NSA (500 m) 14,389 7,993 886 3,925 4,918 8,597 4,305 UCL WA (2 km) 0 0 0 0 0 777 0 Total 12,424 7,228 848 3,515 4,582 8,650 4,147 NSA (500 m) 0.06 0.07 0.20 0.12 0.11 0.06 0.08 Precision WA (2 km) N/A N/A N/A N/A N/A 0.58 0 Total 0.01 0.02 0.04 0.02 0.02 0.01 0.02 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.15: Behaviour (sitting or flying) of common eiders in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 316 195 24 67 83 288 152 Sitting WA (2 km) 0 0 0 0 0 3 0 NSA (500 m) 6 2 0 1 1 1 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.7.2 Distribution

In February / March 2012, common eiders were located close to shore in many groups scattered around the Orkney Islands, Pentland Firth and the Scottish mainland (Figure 5.7: A). Common eiders were recorded as far north as Papa Westray to South Walls in the south of the Orkney Islands, large groups were recorded around Westray, Hoy and South Ronaldsay. Common eiders were also recorded around the island of Stroma in the Pentland Firth to Thurso Bay off the north-east coast of the Scottish mainland (Figure 5.7: A).

During the April / May 2012 survey window, common eiders were again located in several groups scattered between Papa Westray in the north to Sandside Bay off the Scottish mainland (Figure 5.7: B).

In May / June 2012, few common eiders were recorded scattered in small groups across the area. Small groups (3 – 6 birds) were located in the Bay of Pierowall and off Noup Head on Westray. A similar sized group was located between Burray and South Ronaldsay. Smaller groups were located around the Orkney Mainland and Thurso Bay off the Scottish mainland (Figure 5.7: C).

In June /August 2012, common eiders were located in two large groups (11 – 30 birds); one close to the island of Stroma and the other off the north side of South Ronaldsay. Smaller groups were located in the Bay of Ayre on the south side of the Orkney Mainland and near Spo Ness on the northern side of Westray (Figure 5.7: D).

During the August / September 2012 survey the majority of common eiders were located in three large groups (11 – 30 birds) off the north coast of South Ronaldsay and in Echnaloch Bay (Figure 5.7:E). Further large groups (11 – 30 birds) were recorded on the north and south-east coast of the Okrney Mainland near the Bay of Carness and Dingyshowe Bay. Smaller groups (3 - 6 birds) were recorded along the east coast of Rousay and west coast of South Ronaldsay (Figure 5.7: E).

In October / November 2012, common eiders were scattered in groups (+ 30 birds) close to the shore around the Orkney Islands and Pentland Firth, with a pair of individuals located off the north-west tip of the Scottish Mainland (Figure 5.7: F). Groups of common eiders were 38

APEM Final Report 511639 recorded off the north tip of Westray to the Scottish Mainland with the majority of birds located around the north coast of South Ronaldsay, Orkney Mainland and Shapinsay, with groups of individuals also located south and west of Rousay and north of Westray (Figure 5.7: F).

During the December 2012 / January 2013, multiple groups of varying sizes were recorded between the northern tip of Orkney Island and Thieves Holm north of the Orkney Mainland (Figure 5.7: G). Two large groups (7 – 30 birds) were recorded on the north-east coasts of the Orkney Mainland with other clusters observed off the eastern side of Hoy, along the coasts of South Ronaldsay and north of Banff on the Scottish Mainland (Figure 5.7:G).

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Figure 5.7: Distribution of common eiders recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.8 Long-tailed ducks

5.1.8.1 Abundance estimates

Data presented in Table 5.16 refer to long-tailed ducks. Small numbers of long-tailed ducks were recorded in all survey windows except June / August 2012 and August / September 2012. Numbers peaked in February / March 2012 when the relative population was estimated at 3,171 (158 – 6,690) birds. All long-tailed ducks were recorded within the near shore area.

Table 5.16: Raw counts, number of sightings, population estimates, confidence limits and precision for long-tailed ducks in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 158 1 12 0 0 58 23 Count WA (2 km) 0 0 0 0 0 0 0 Total 158 1 12 0 0 58 23 NSA (500 m) 9 1 10 0 0 17 7 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 9 1 10 0 0 17 7 NSA (500 m) 3,171 19 253 0 0 1,253 434 Population WA (2 km) 0 0 0 0 0 0 0 Total 3,171 19 253 0 0 1,253 434 NSA (500 m) 301 1 105 0 0 259 94 LCL WA (2 km) 0 0 0 0 0 0 0 Total 158 1 92 0 0 58 48 NSA (500 m) 7,405 78 443 0 0 2,981 887 UCL WA (2 km) 0 0 0 0 0 0 0 Total 6,690 56 414 0 0 2,723 820 NSA (500 m) 0.08 >1 0.29 N/A N/A 0.13 0.21 Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total 0.02 0.23 0.06 N/A N/A 0.03 0.05 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.17: Behaviour (sitting or flying) of long-tailed ducks in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 158 1 12 0 0 57 23 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 0 0 1 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.8.2 Distribution

In February / March 2012, two large groups of long-tailed ducks (> 31 birds) were recorded; one in Rysa Sound on the eastern side of Hoy and another in Veantrow Bay on the northern side of Shapinsay. A slightly smaller group (11 – 30 birds) was recorded in the Bay of Skaill within 1 km of the north-east coast of Westray. Small groups (1 – 2 birds) were recorded close to shore scattered throughout the Orkney Isles including Eynhallow Sound and Bay of Isbister off the north coast Mainland Orkney, Gutter Sound off Fara and Water Sound off Burray (Figure 5.8: A).

During the April / May 2012 survey window, one long-tailed duck was recorded in Fersness Bay on the west side of Eday (Figure 5.8: B).

In May / June 2012, small groups of long-tailed ducks were recorded close to land and scattered throughout the survey site from Skea Skerries off the south coast of Westray in the north of the site to Dunnet Bay, Thurso Bay and the head of Loch Eriboll off mainland Scotland in the south of the site (Figure 5.8: C).

In October / November 2012, a large group (+ 31 birds) was recorded along the north coast of the Orkney Mainland near the Broch of Gurness, with numerous small groups (<6 birds) of long-tailed ducks recorded along the west coast of Eday, Shapinsay and Stronsay and along the north coast of the Orkney Mainland, South Ronaldsay and Flotta (Figure 5.8:D).

During the December 2012 / January 2013, one moderate group of long-tailed ducks were recorded to the west of Papa Westray in Papa Sound, with smaller groups and individuals observed in the Bay of Firth and in the Bay of Kirkwall off the Orkney Mainland, within North Bay south of Hoy and north of East Mey on the Scottish Mainland (Figure 5.8:F).

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Figure 5.8: Distribution of long-tailed ducks recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: October / November 2012

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E: December 2012 / January 2013

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5.1.9 Common scoter

5.1.9.1 Abundance estimates

Data presented in Table 5.18 refer to common scoter. Small numbers of common scoter were recorded in October / November 2012 when the relative population was estimated at 972 (45 – 2,752) birds. All common scoter were recorded within the near shore area.

Table 5.18: Raw counts, number of sightings, population estimates, confidence limits and precision for common scoter in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 45 0 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 45 0 NSA (500 m) 0 0 0 0 0 2 0 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 0 0 0 0 0 2 0 NSA (500 m) 0 0 0 0 0 972 0 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 972 0 NSA (500 m) 0 0 0 0 0 45 0 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 45 0 NSA (500 m) 0 0 0 0 0 2,873 0 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 2,752 0 NSA (500 m) N/A N/A N/A N/A N/A 0.15 N/A Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total N/A N/A N/A N/A N/A 0.03 N/A Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.19: Behaviour (sitting or flying) of common scoter in the PFOW area for each survey. Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 45 0 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 0 0 0 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.9.2 Distribution

During the October / November 2012 survey window, a large group (+ 31 birds) was recorded close to Burwick on the south-west coast of South Ronaldsay. A smaller group (2 birds) was recorded in Eynhallow Sound on the northern side of the Orkney Mainland (Figure 5.9 A).

Figure 5.9: Distribution of common scoter recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: October / November 2012

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5.1.10 Goldeneye

5.1.10.1 Abundance estimates

Data presented in Table 5.20 refer to goldeneye. Small numbers of goldeneye were recorded in April / May 2012, October / November 2012 and December 2012 / January 2013 surveys. Numbers peaked in October / November 2012 when the relative population was estimated at 799 (147 – 1,451) birds. All goldeneye were recorded within the near shore area.

Table 5.20: Raw counts, number of sightings, population estimates, confidence limits and precision for goldeneye in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 2 0 0 0 37 20 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 2 0 0 0 37 20 NSA (500 m) 0 1 0 0 0 10 9 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 0 1 0 0 0 10 9 NSA (500 m) 0 39 0 0 0 799 378 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 39 0 0 0 799 378 NSA (500 m) 0 2 0 0 0 259 94 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 2 0 0 0 147 762 NSA (500 m) 0 155 0 0 0 1,598 869 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 113 0 0 0 1,451 20 NSA (500 m) N/A 0.71 N/A N/A N/A 0.16 0.22 Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total N/A 0.16 N/A N/A N/A 0.04 0.05 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.21: Behaviour (sitting or flying) of goldeneye in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 2 0 0 0 36 20 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 0 0 1 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.10.2 Distribution

In April / May 2012 survey window, two goldeneyes were recorded together in Kirk Hope, within 1 km off South Walls (Figure 5.10: A).

During the October / November 2012 survey window, concentrations of goldeneye were recorded north of Hoxa on South Ronaldsay, off the south-west tip of Burray and in Echnaloch Bay also off Burray (Figure 5.8:B). Smaller groups of goldeneye were located in the Bay of Firth, Inganess Bay and near the Bay of Ayre on the Orkney Mainland, with one small group located on the northern coastline of Graemsay (Figure 5.10: B).

In December 2012 / January 2013, two groups of goldeneye were recorded in Swanbister Bay and off Houton Head close to the coast of the Orkney Mainland (Figure 5.8: C). Individuals were also observed close to the north and south coasts of South Ronaldsay and off the north- west coast of Hunda (Figure 5.10:C).

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Figure 5.10: Distribution of goldeneye recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: April / May 2012 B: October / November 2012

C: December 2012 / January 2013

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5.1.11 Red-breasted mergansers

5.1.11.1 Abundance estimates

Data presented in Table 5.22 refer to red-breasted mergansers. Small numbers of red- breasted mergansers were recorded in February / March 2012, October / November 2012 and December 2012 / January 2013 surveys. Numbers peaked in October / November 2012 when the relative population was estimated at 605 (66 – 1,143) birds. All red-breasted mergansers were recorded within the near shore area.

Table 5.22: Raw counts, number of sightings, population estimates, confidence limits and precision for red-breasted mergansers in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 29 0 0 0 0 28 7 Count WA (2 km) 0 0 0 0 0 0 0 Total 29 0 0 0 0 28 7 NSA (500 m) 7 0 0 0 0 9 4 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 7 0 0 0 0 9 4 NSA (500 m) 582 0 0 0 0 605 132 Population WA (2 km) 0 0 0 0 0 0 0 Total 582 0 0 0 0 605 132 NSA (500 m) 140 0 0 0 0 194 19 LCL WA (2 km) 0 0 0 0 0 0 0 Total 99 0 0 0 0 66 7 NSA (500 m) 1,124 0 0 0 0 1,253 302 UCL WA (2 km) 0 0 0 0 0 0 0 Total 1,065 0 0 0 0 1,143 272 NSA (500 m) 0.19 N/A N/A N/A N/A 0.19 0.38 Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total 0.04 N/A N/A N/A N/A 0.04 0.09 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.23: Behaviour (sitting or flying) of red-breasted mergansers in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 28 0 0 0 0 28 7 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 1 0 0 0 0 0 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.11.2 Distribution

In February / March 2012, 29 red-breasted mergansers were located in several groups close to shore around Westray, off the Bay of Kirbist and Bay of Tuquoy, and Papa Westray off Noup Head. Other groups were located off Costa Head on the northern side of the Orkney Mainland and Point of Bizber on the south side of the Orkney Mainland (Figure 5.11: A).

During the October / November 2012 survey window, a large group (11 – 30 birds) of red- breasted mergansers was recorded within Deer Sound on the Orkney Mainland. A smaller group (3 - 6 birds) was recorded north-west of Wyre near the Bay of Whelkmulli and smaller groups (1 – 2 birds) were recorded along the north coast of the Orkney Mainland and Westray with one individual observed in open water between South Ronaldsay and the Orkney Mainland (Figure 5.11: B)

In December 2012 / January 2013, the largest group (3 – 6 birds) was recorded off the north coast of Orkney Island, with three smaller clusters observed in the Bay of Kirkwall on the Orkney Mainland, on the north coast of Burray and close to the coast of Bow Head on Westray (Figure 5.11:C).

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Figure 5.11: Distribution of red-breasted merganser recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: October / November 2012

C: December 2012 / January 2013 53

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5.1.12 Total divers

5.1.12.1 Abundance estimates

Data presented in Table 5.24 refer to total divers (including red-throated, black-throated, great northern and divers not identified to species level). Small to moderate numbers of divers were recorded in all survey windows except August / September 2012. Numbers peaked in February / March 2012 when the relative population was estimated at 1,830 (968 – 2,691) birds. Divers were recorded both within the near shore area and wider area. The proportion of divers identified to species level is presented in Table 5.26. Relative population estimates for divers that could be identified to species are provided in subsequent sections. The majority of divers not identified to species are likely to have been red-throated divers, as the main confusion species, black-throated divers, are comparatively scarce around the Orkney Isles.

Table 5.24: Raw counts, number of sightings, population estimates, confidence limits and precision for total divers in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 65 15 12 4 0 46 28 Count WA (2 km) 6 1 1 0 0 0 4 Total 71 16 13 4 0 46 32 NSA (500 m) 40 11 11 4 0 30 26 Number of WA (2 km) 3 1 1 0 0 0 3 sightings Total 43 12 12 4 0 30 29 NSA (500 m) 1,304 291 253 98 0 994 529 Population WA (2 km) 525 79 94 0 0 0 418 Total 1,830 370 347 98 0 994 947 NSA (500 m) 863 116 105 24 0 540 321 LCL WA (2 km) 6 1 1 0 0 0 4 Total 968 118 110 4 0 425 408 NSA (500 m) 1,846 524 422 195 0 1,728 755 UCL WA (2 km) 1,313 238 282 0 0 0 941 Total 2,691 623 584 191 0 1,562 1,486 NSA (500 m) 0.12 0.26 0.29 0.5 N/A 0.15 0.19 Precision WA (2 km) 0.41 >1 >1 N/A N/A N/A 0.5 Total 0.02 0.05 0.05 0.10 N/A 0.03 0.03 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.25: Behaviour (sitting or flying) of total divers in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 64 15 11 4 0 46 26 Sitting WA (2 km) 6 1 1 0 0 0 3 NSA (500 m) 1 0 1 0 0 0 2 Flying WA (2 km) 0 0 0 0 0 0 1

Table 5.26: Total number of each species of diver recorded.

Red-throated Black-throated Great Unidentified Survey window divers divers Northern diver divers Feb / Mar 2012 0 0 24 47 Apr / May 2012 0 0 7 9 May / Jun 2012 0 0 6 7 Jun / Aug 2012 0 0 0 4 Aug / Sep 2012 0 0 0 0 Oct / Nov 2012 27 0 7 12 Dec 2012 / 21 1 8 2 Jan 2013

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5.1.12.2 Distribution

In February / March 2012, the majority of divers were located close to shore within 2-3 km of land. Divers were located in many groups scattered around the Orkney Islands and the Scottish Mainland, stretching from Papa Westray in the north to Dunnet Bay in the south. Moderate congregations were recorded in Scapa Flow as well as off Papa Westray, around South Ronaldsay and Sanday (Figure 5.12: A).

In April / May 2012, fewer divers were recorded; the largest group (7 – 10 birds) was located on the eastern side of South Ronaldsay within 3 km of land. Other smaller groups were scattered around Westray and Burray (Figure 5.12: B).

During the May / June 2012 survey window, divers were located in a few small groups scattered around Westray and Sanday in the north and Papa Westray in the south (Figure 5.12: C).

In June / August 2012, four single divers were recorded, two in the Bay of Whelkmulli off Wyre, one in the Bay of Tuquoy off Westray and one off the south-west tip of Stronsay (Figure 5.12: D).

In October / November 2012, the majority of divers were located close to the shore within 3 km of land. Divers were recorded in multiple small groups around the Orkney Islands from the north-east tip of Westray to north of Crosskirk on the Scottish Mainland (Figure 5.12: E). The largest group (11 - 31 birds) was recorded off the north coast of the Orkney Mainland within Eynhallow Sound (Figure 5.12: E).

During the December 2012 / January 2013 survey window, divers were recorded close to shore and within the wider area in many small groups around the Orkney Islands, Pentland Firth islands and off the north-east coast of the Scottish mainland (Figure 5.12: F). Larger group of divers (3 – 6 birds) were recorded in open water to the north of Papa Westray, in the Bay of Kirkwall on the Orkney Mainland and off Mirkady Point also on the Orkney Mainland (Figure 5.12:F).

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Figure 5.12: Distribution of total divers recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: October / November 2012 F: December 2012 / January 2013

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5.1.13 Red-throated divers

5.1.13.1 Abundance estimates

Data presented in Table 5.27 refer to red-throated divers. Small numbers of red-throated divers were recorded in October / November 2012 and December 2012 / January 2013. The relative population peaked in October / November 2012 at an estimated 583 (246 – 921) birds. The majority of red-throated divers were recorded within the near shore area.

Table 5.27: Raw counts, number of sightings, population estimates, confidence limits and precision for red-throated divers in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 27 18 Count WA (2 km) 0 0 0 0 0 0 3 Total 0 0 0 0 0 27 21 NSA (500 m) 0 0 0 0 0 18 17 Number of WA (2 km) 0 0 0 0 0 0 2 sightings Total 0 0 0 0 0 18 19 NSA (500 m) 0 0 0 0 0 583 340 Population WA (2 km) 0 0 0 0 0 0 314 Total 0 0 0 0 0 583 654 NSA (500 m) 0 0 0 0 0 302 189 LCL WA (2 km) 0 0 0 0 0 0 3 Total 0 0 0 0 0 246 170 NSA (500 m) 0 0 0 0 0 972 510 UCL WA (2 km) 0 0 0 0 0 0 941 Total 0 0 0 0 0 921 1,137 NSA (500 m) N/A N/A N/A N/A N/A 0.19 0.24 Precision WA (2 km) N/A N/A N/A N/A N/A N/A 0.58 Total N/A N/A N/A N/A N/A 0.04 0.04 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.28: Behaviour (sitting or flying) of red-throated divers in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 27 17 Sitting WA (2 km) 0 0 0 0 0 0 2 NSA (500 m) 0 0 0 0 0 0 1 Flying WA (2 km) 0 0 0 0 0 0 1

5.1.13.2 Distribution

In October / November 2012, several small groups (<7 in each) were recorded around the Orkney Mainland, in Eynhallow Sound and the water between the Orkney Mainland and Shapinsay. Further small groups were recorded along the north coast of Wyre, off the southern tip of Orkney Island, off the south and west coast of Westray and north-west of South Ronaldsay (Figure 5.13:A).

During the December 2012 / January 2013 survey window, the largest groups of red-throated divers were recorded north of Papa Westray in open water and off Mirkady Point on the Orkney Mainland (Figure 5.13: B). The remaining red-throated divers were scattered along the north coasts of Westray and the Orkney Mainland, the east coast of Rousay and the west coasts of Shapinsay and the Orkney Mainland. Individual red-throated divers were also recorded north of Scarfskerry and Tongue on the Scottish Mainland (Figure 5.13:C).

APEM Final Report 511639

Figure 5.13: Distribution of red-throated divers recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A:October / November 2012 B: December 2012 / January 2013

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5.1.14 Black-throated divers

5.1.14.1 Abundance estimates

Data presented in Table 5.29 refer to black-throated divers. One black-throated diver was recorded in the near shore area during the December 2012 / January 2013 survey window.

Table 5.29: Raw counts, number of sightings, population estimates, confidence limits and precision for black-throated divers in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 0 1 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 0 1 NSA (500 m) 0 0 0 0 0 0 1 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 0 0 0 0 0 0 1 NSA (500 m) 0 0 0 0 0 0 19 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 0 19 NSA (500 m) 0 0 0 0 0 0 1 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 0 1 NSA (500 m) 0 0 0 0 0 0 57 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 0 55 NSA (500 m) N/A N/A N/A N/A N/A N/A >1 Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total N/A N/A N/A N/A N/A N/A 0.23 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.30: Behaviour (sitting or flying) of black-throated divers in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 0 1 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 0 0 0 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.14.2 Distribution

During the December 2012 / January 2013 survey window, one black-throated diver was recorded at the mouth of the Bay of Tuquoy, south of Garth on Westray (Figure 5.14: A).

Figure 5.14 : Distribution of black-throated divers recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: December 2012 / January 2013

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5.1.15 Great-northern divers

5.1.15.1 Abundance estimates

Data presented in Table 5.31 refer to great-northern divers. Small numbers of great-northern divers were recorded in all survey windows except June / August 2012 and August / September 2012. Numbers peaked in February / March 2012 when the relative population was estimated at 617 (213 – 1,021) birds. Great-northern divers were recorded both within the near shore area and wider area, although the estimated relative population was higher within the near shore area.

Table 5.31: Raw counts, number of sightings, population estimates, confidence limits and precision for great-northern divers in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 22 6 5 0 0 7 8 Count WA (2 km) 2 1 1 0 0 0 0 Total 24 7 6 0 0 7 8 NSA (500 m) 17 6 5 0 0 7 8 Number of WA (2 km) 1 1 1 0 0 0 0 sightings Total 18 7 6 0 0 7 8 NSA (500 m) 441 116 105 0 0 151 151 Population WA (2 km) 175 79 94 0 0 0 0 Total 617 196 200 0 0 151 151 NSA (500 m) 241 19 21 0 0 43 57 LCL WA (2 km) 2 1 1 0 0 0 0 Total 213 17 6 0 0 42 49 NSA (500 m) 662 233 211 0 0 259 264 UCL WA (2 km) 525 238 376 0 0 0 0 Total 1,021 375 404 0 0 260 253 NSA (500 m) 0.21 0.41 0.45 N/A N/A 0.38 0.35 Precision WA (2 km) 0.71 >1 >1 N/A N/A N/A N/A Total 0.04 0.07 0.07 N/A N/A 0.08 0.08 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.32: Behaviour (sitting or flying) of great northern divers in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 22 6 4 0 0 7 8 Sitting WA (2 km) 2 1 1 0 0 0 0 NSA (500 m) 0 0 1 0 0 0 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.15.2 Distribution

In February / March 2012, several small groups (1-2 birds in each) were recorded close to shore (< 1 km) scattered throughout the Orkney Isles from North Wick off Papa Westray in the north of the site to Brough Ness off South Ronaldsay in the south of the site (Figure 5.15: A).

During the April / May 2012 survey window, a similar distribution to February / March was recorded, although there were fewer groups (1-2 birds in each) in total (Figure 5.15: B).

In May / June 2012, five single sightings of great-northern divers were recorded close to land scattered from Eday Sound in the north of the site to Brough Ness in the south of the site (Figure 5.15: C).

During the October / November 2012 survey window, several individual great northern divers were recorded along the north-east coast of South Ronaldsay, south of the Orkney Mainland within St Mary’s Bay and north of Flotta. Individuals were also located in the north of the site, west of Stronsay and Eday (Figure 5.15: D).

In December 2012 / January 2013, eight single sightings of great northern divers were recorded, east of Northtown on Burray, in water between Hoy and Cava, on the east coast of Graemsay, in the Bay of Firth and Wide Firth off the Orkney Mainland and on the north coast of Wyre and in water between Wyre and Gaiesay (Figure 5.15:E).

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Figure 5.15: Distribution of great-northern divers recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D:October / November 2012

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E: December 2012 / January 2013

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5.1.16 Fulmars

5.1.16.1 Abundance estimates

Data presented in Table 5.33 refer to fulmars. Fulmars were the most numerous bird species recorded in the PFOW area and large numbers were recorded in all survey windows. Numbers peaked in the December 2012 / January 2013 survey window when the relative population was estimated at 53,384 (42,282 – 64,486) birds. Fulmars were recorded both within the near shore area and wider area, although the estimated relative population was higher within the near shore area.

Table 5.33: Raw counts, number of sightings, population estimates, confidence limits and precision for fulmars in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 1,380 557 474 840 423 678 2,196 Count WA (2 km) 77 57 31 70 93 119 114 Total 1,457 614 505 910 516 797 2,310 NSA (500 m) 296 209 201 279 211 149 341 Number of WA (2 km) 66 31 28 54 79 48 85 sightings Total 362 240 229 333 290 197 426 NSA (500 m) 27,694 10,806 9,997 20,476 13,002 14,645 41,464 Population WA (2 km) 6,742 4,527 2,915 6,128 10,505 10,270 11,920 Total 34,435 15,332 12,913 26,604 23,508 24,915 53,384 NSA (500 m) 21,473 8,420 7,551 14,772 10,390 9,482 31,476 LCL WA (2 km) 5,166 1,906 1,975 4,202 8,246 4,747 9,306 Total 27,497 10,846 10,143 20,111 19,914 16,214 42,282 NSA (500 m) 35,400 13,677 12,423 27,058 15,707 20,455 52,434 UCL WA (2 km) 8,580 8,815 4,044 8,404 13,103 18,297 14,638 Total 41,374 19,819 15,682 33,098 27,101 33,616 64,486 NSA (500 m) 0.03 0.04 0.05 0.03 0.05 0.04 0.02 Precision WA (2 km) 0.11 0.13 0.18 0.12 0.1 0.09 0.09 Total 0.01 0.01 0.01 0.01 0.01 0.01 0 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.34: Behaviour (sitting or flying) of fulmars in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 Mar May Jun Aug Sep Nov / Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 237 180 243 327 114 92 243 Sitting WA (2 km) 8 24 4 23 28 28 14 NSA (500 m) 1,143 377 231 513 309 586 1953 Flying WA (2 km) 69 33 27 47 65 91 100

5.1.16.2 Distribution

In February / March 2012, large numbers of fulmars were distributed all over the PFOW survey area, both close to shore and offshore, although numbers were greater within 3 km of shore (Figure 5.16: A). Fulmars were concentrated around the north-west side of Westray, the northern side of Eday and Sanday, the northern side of Rousay, the northern side of Orkney Mainland, the western side of Hoy and along the northern Scottish mainland coast (Figure 5.16: A).

In April / May 2012, fewer fulmars were located in the north of the site, although some groups were still located around the north side of Eday and Rousay (Figure 5.16: B). Large concentrations were still located around the north and west of Orkney Mainland, the western side of Hoy, the eastern side of South Ronaldsay and the northern Scottish mainland coast. Small groups of fulmars were scattered widely beyond 3 km of the coastline.

During the May / June 2012 survey window, fulmars were concentrated around the southern Orkney Islands including the west coast of Hoy, South Ronaldsay and the west coast of the Orkney Mainland with many small groups scattered throughout the Pentland Firth (Figure 5.16: C).

In June / August 2012, large concentrations of fulmars were located around the west coast of Hoy, South Ronaldsay and west coast Orkney Mainland. Large groups were also located off Rousay, Eday and Papa Westray while smaller groups were regularly located between the Orkney Isles and along the Scottish mainland coast (Figure 5.16: D).

In August / September 2012 fulmars were distributed all over the PFOW survey area, both close to shore and offshore, with higher numbers recorded close to shore (Figure 5.16: E). Fulmars were concentrated north of Drum Hollistan and on the far north-east tip of the Scottish Mainland. High numbers of fulmars were located to the south and west of South Ronaldsay, Hoy, Graemsay and the Orkney Mainland. A further large group (11 - 30 birds) was recorded at the northern tip of Eday, with fulmars also recorded in open water in the north and west of the survey area (Figure 5.16: E).

During the October / November 2012 survey window, fulmars were concentrated to the west of Hoy and Graemsay, along the south-east coast of South Ronaldsay and north-west of Eday with many small groups scattered throughout the Pentland Firth (Figure 5.16: F) 69

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Peak numbers of Fulmars were recorded during the December 2012 / January 2013 survey window, with a similar distribution to the February / March 2012 survey. The highest concentrations of fulmars were recorded to the west of Hoy within the SPA. (Figure 5.16: G).

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Figure 5.16: Distribution of fulmars recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August /September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.17 Gannets

5.1.17.1 Abundance estimates

Data presented in Table 5.35 refer to gannets. Small numbers of gannets were recorded in all survey windows. Numbers peaked in August / September 2012 when the relative population was estimated at 9,047(5,544 –12,550) birds. Gannets were recorded both within the near shore area and wider area.

Table 5.35: Raw counts, number of sightings, population estimates, confidence limits and precision for gannets in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 6 65 37 125 151 45 1 Count WA (2 km) 0 17 13 21 39 7 2 Total 6 82 50 146 190 52 3 NSA (500 m) 6 52 21 31 70 33 1 Number of WA (2 km) 0 15 11 8 25 6 2 sightings Total 6 67 32 39 95 39 3 NSA (500 m) 120 1,261 780 3,047 4,642 972 19 Population WA (2 km) 0 1,350 1,223 1,838 4,405 604 209 Total 120 2,611 2,003 4,886 9,047 1,576 228 NSA (500 m) 40 892 380 1,024 2,797 648 1 LCL WA (2 km) 0 715 470 350 2,146 173 2 Total 27 1,806 1,090 1,774 5,544 957 3 NSA (500 m) 221 1,707 1,287 6,143 6,978 1,339 57 UCL WA (2 km) 0 2,065 2,069 3,940 7,568 12,08 523 Total 214 3,416 2,916 7,997 12,550 2,195 519 NSA (500 m) 0.41 0.12 0.16 0.09 0.08 0.15 >1 Precision WA (2 km) N/A 0.24 0.28 0.22 0.16 0.38 0.71 Total 0.09 0.02 0.02 0.01 0.01 0.03 0.07 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.36: Behaviour (sitting or flying) of gannets in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 3 18 18 14 47 8 0 Sitting WA (2 km) 3 4 6 11 13 3 0 NSA (500 m) 3 47 19 11 104 37 1 Flying WA (2 km) 3 13 7 10 26 4 2

5.1.17.2 Distribution

In February / March 2012, gannets were thinly distributed with individuals recorded off the north-west tips of Westray and Rousay, off the east coast of Shapinsay and near to Tingwall on Orkney Mainland. Two gannets were also recorded close together in St. Peter’s Bay on Orkney Mainland during this survey (Figure 5.17: A).

During the April / May 2012 survey window, gannet numbers had increased compared to the previous survey window. Gannets were recorded all along the north coast of the Scottish mainland, with concentrations to the west of Brims Ness and the east of Dunnet Head (Figure 5.17: B). Gannets were also recorded to the west of the Orkney archipelagos, with concentrations of individuals identified to the west and north of Westray and Papa Westray and off Marwick Head on Orkney Mainland (Figure 5.17: B). Gannets were also recorded further offshore during this survey window towards the western boundary of the wider survey area (Figure 5.17: B).

In May / June 2012, gannet numbers were reduced and widely distributed across the PFOW survey area (Figure 5.17: C). Concentrations of gannets were recorded to the north of Costa Head on Orkney Mainland, east of Shapinsay in the Stronsay Firth, off Noup Head on Westray and to the north of Bow Head, also on Westray (Figure 5.17: C).

During the June / August 2012 survey window, gannets numbers has increased, although individuals were less dispersed than during previous months (Figure 5.17: D). Concentrations of individuals were identified between Strathy Point and the Kyle of Tongue and off Duncansby Head along the northern coast of mainland Scotland, off Bring Head on the western coast of Rousay and off Noup Head on Westray (Figure 5.17: D). Further aggregations of gannets were recorded to the north of Westray and towards the far western boundary of the wider PFOW survey area (Figure 5.17: D).

In August / September 2012, gannets were concentrated in the south-west of the survey area close to coast of the Scottish mainland with a further large group (+31 birds) to the east of Duncansby Head (Figure 5.17:E). Other large groups were recorded within Eynhallow Sound and west of Woodwick off the Orkney Mainland and < 3 km from the south and north-west shores of Westray. Smaller groups (<7 individuals) were scattered throughout the Orkney island and in open water in the north-west of the survey area (Figure 5.17: E).

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During the October / November 2012 survey window, gannet numbers decreased compared to the previous survey window and were widely distributed across the PFOW survey area (Figure 5.17:F). Concentrations of gannets were recorded off Duncansby Head close to the north coast of the Scottish mainland, in open water between Flotta and South Ronaldsay, south of Veness off Eday and west of the Point of Neven on Westray (Figure 5.17 :F).

In December 2012 / January 2013, three single sightings of gannets were recorded, with one individual observed close to the coast of the Scottish Mainland north of Tongue. The remaining two gannets were recorded in open water to the west of Hoy close to the Pentland Firth Survey Area boundary and to the east of Papa Westray (Figure 5.17:G).

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Figure 5.17: Distribution of gannets recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.18 Total cormorants & shags

5.1.18.1 Abundance estimates

Data presented in Table 5.37 refer to total cormorants and shags (including cormorants, shags and cormorants / shags that were not identified to species). Small numbers of cormorants / shags were recorded in all survey windows except February / March 2012. Numbers peaked in December 2012 / January 2013 when the relative population was estimated at 1,359 (72 – 2,865) birds. All cormorants / shags were recorded within the near shore area. The numbers of cormorants / shags identified to species level is presented in Table 5.39. Relative population estimates for cormorants / shags that could be identified to species are provided in subsequent sections.

Table 5.37: Raw counts, number of sightings, population estimates, confidence limits and precision for total cormorants & shags in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 1 1 5 39 29 72 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 1 1 5 39 29 72 NSA (500 m) 0 1 1 4 11 24 22 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 0 1 1 4 11 24 22 NSA (500 m) 0 19 21 122 1,199 626 1,359 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 19 21 122 1,199 626 1,359 NSA (500 m) 0 1 1 24 369 346 359 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 1 1 5 288 363 72 NSA (500 m) 0 58 63 268 2,305 907 3,021 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 56 61 246 2,110 890 2,865 NSA (500 m) N/A >1 >1 0.45 0.16 0.19 0.12 Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total N/A 0.23 0.22 0.09 0.03 0.04 0.03 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.38: Behaviour (sitting or flying) of total cormorants and shags in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar20 May Jun Aug /Sep Nov Jan 12 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 1 0 3 30 10 63 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 1 2 9 19 9 Flying WA (2 km) 0 0 0 0 0 0 0

Table 5.39: Total number of cormorants & shags recorded.

Survey window Cormorants Shags Shags or Cormorants Feb / Mar 2012 0 0 0 Apr / May 2012 0 1 0 May / Jun 2012 0 1 0 Jun / Aug 2012 0 4 1 Aug / Sep 2012 2 37 0 Oct / Nov 2012 2 27 0 Dec 2012 / Jan 2013 1 71 0

5.1.18.2 Distribution

During the April / May 2012 survey window, one shag was recorded off Sandside Bay on the northern coast of the Scottish mainland (Figure 5.18: A).

In May / June 2012, one shag was recorded within 1 km off Noup Head off Westray (Figure 5.18: B).

In June / August 2012, four shags were recorded; one individual was located along the northern coast of mainland Scotland near to Sandside Bay, two shags were located off Brough Ness on South Ronaldsay and a further shag was located off Berst Ness on the southern coast of Westray (Figure 5.18: C). An additional cormorant or shag was recorded in flight off Noup Head on Westray during the July 2012 survey window (Figure 5.18: C).

During the August / September 2012 survey cormorant / shag numbers increased, including 37 shags and two cormorants, with the majority recorded along the coast of mainland Scotland between Fresgoe and Skerray. The two cormorants were recorded in Tongue Bay off the Scottish mainland (Figure 5.18: D). Small groups were recorded in Echnaloch Bay off the north coast of South Ronaldsay, west of Glen View off the south coast of the Orkney mainland, south of Langskaill on Westray and west of Aikerness, also off Westray (Figure 5.18: D).

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In October / November 2012, 29 shags were scattered throughout the Orkney Islands with the largest group (3 – 6 birds) recorded along the west coast of the Orkney Mainland in the Bay of Skaill. Pairs of shags were recorded south of Spur Ness off Sanday, in Swanbister Bay off the Orkney Mainland and off the Head of Holland also off the Orkney Mainland (Figure 5.18: E).The two cormorants were recorded off the north-east tip of Burray and within Papa Sound between Westray and Papa Westray (Figure 5.18: E).

During the December 2012 / January 2013 survey window, a large group (+ 31 birds) was recorded on the east Pentland Firth Survey Area boundary, north of Sanday (Figure 5.18: F), with pairs and smaller groups (3 -6 birds) of shags recorded in the Bay of Sandsgarth off the south of Shapinsay, north of Quanterness on the Orkney Mainland and to the east of South Walls, south of Flotta (Figure 5.18: G). One cormorant was recorded in Inganess Bay, east of Yinstay on the Orkney Mainland (Figure 5.18: F).

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Figure 5.18: Distribution of total cormorants & shags recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: April / May 2012 B: May / June 2012

C: June / August 2012 D: August / September 2012

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E: October / November 2012 F: December 2012 / January 2013

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5.1.19 Cormorants

5.1.19.1 Abundance estimates

Data presented in Table 5.40 refer to cormorants. Small numbers of cormorants were recorded in the August / September 2012, October / November 2012 and December 2012 / January 2013 survey windows. Numbers peaked in August / September when the relative population was estimated at 61 (2 – 180) birds. All cormorants were recorded within the near shore area.

Table 5.40 : Raw counts, number of sightings, population estimates, confidence limits and precision for cormorants in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 2 2 1 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 2 2 1 NSA (500 m) 0 0 0 0 1 2 1 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 0 0 0 0 1 2 1 NSA (500 m) 0 0 0 0 61 43 19 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 61 43 1 NSA (500 m) 0 0 0 0 2 2 1 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 2 2 1 NSA (500 m) 0 0 0 0 184 130 57 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 180 102 55 NSA (500 m) N/A N/A N/A N/A 0.71 0.71 >1 Precision WA (2 km) N/A N/A N/A N/A N/A N/A 0 Total N/A N/A N/A N/A 0.13 0.15 0.23 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.41: Behaviour (sitting or flying) of cormorants in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 1 0 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 0 2 1 1 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.19.2 Distribution

During the August / September 2012 survey window, two cormorants were recorded in Tongue Bay off the Scottish mainland (Figure 5.19: A).

In the October / November survey, two individual cormorants were recorded off the north- east tip of Burray and within Papa Sound between Westray and Papa Westray (Figure 5.19: B).

During the December 2012 / January 2013 survey window, one cormorant was recorded in Inganess Bay, east of Yinstay on the Orkney Mainland (Figure 5.19:C).

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Figure 5.19: Distribution of cormorants recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: August / September 2012 B: October / November 2012

C: December 2012 / January 2013

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5.1.20 Shags

5.1.20.1 Abundance estimates

Data presented in Table 5.42 refer to shags. Small numbers of shags were recorded in all survey windows except February / March 2012. Numbers peaked in the December 2012 / January 2013 survey window when the relative population was estimated at 1,341 (71 – 2,845) birds. All shags were recorded within the near shore area. The shag population estimates in Table 5.42 underestimate the absolute abundance, as shags may spend some 41% of their time at sea under water (see Appendix IV).

Table 5.42 : Raw counts, number of sightings, population estimates, confidence limits and precision for shags in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 1 1 4 37 27 71 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 1 1 4 37 27 71 NSA (500 m) 0 1 1 3 10 22 21 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 0 1 1 3 10 22 21 NSA (500 m) 0 19 21 98 1,137 583 1,341 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 19 21 98 1,137 583 1,341 NSA (500 m) 0 1 1 4 400 324 359 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 1 1 4 243 326 71 NSA (500 m) 0 58 63 244 2,213 842 3,059 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 56 61 212 2,041 840 2,845 NSA (500 m) N/A >1 >1 0.5 0.16 0.19 0.12 Precision WA (2 km) N/A N/A N/A N/A 0 N/A 0 Total N/A 0.23 0.22 0.1 0.03 0.04 0.03 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.43: Behaviour (sitting or flying) of shags in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 1 0 3 30 9 63 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 1 1 7 18 8 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.20.2 Distribution

In April / May 2012 survey window, one shag was recorded off Sandside Bay on the northern coast of the Scottish mainland (Figure 5.20: A).

In May / June 2012 survey window, one shag was recorded within 1 km off Noup Head off Westray (Figure 5.20: B).

In June / August 2012 survey window, four shags were recorded; one individual was located along the northern coast of mainland Scotland near to Sandside Bay, two shags were located off Brough Ness on South Ronaldsay and a further shag was located off Berst Ness on the southern coast of Westray (Figure 5.20: C).

During the August / September 2012 survey window, shag numbers increased compared to previous survey windows, with large groups of shags recorded along the coast of the Scottish mainland from Midfiled to Dounreay, with smaller groups recorded north of Burray in Echnaloch Bay, west of Glen View off mainland Orkney, off Berst Ness off Westray and in Papa Sound between Westray and Papa Westray (Figure 5.20: D).

In October / November 2012, shags were distributed throughout the Orkney Islands with the largest group (3 – 6 birds) recorded along the west coast of the Orkney Mainland in the Bay of Skaill. Pairs of shags were recorded south of Spur Ness off Sanday, in Swanbister Bay off the Orkney Mainland and off the Head of Holland also off the Orkney Mainland (Figure 5.20: E).

The peak number of shags was recorded during the December 2012 / January 2013 survey window, a large group (+ 31 birds) was recorded on the east Pentland Firth Survey Area boundary, north of Sanday (Figure 5.20: F), with pairs and smaller groups (3 -6 birds) of shags recorded in the Bay of Sandsgarth off the south of Shapinsay, north of Quanterness on the Orkney Mainland and to the east of South Walls, south of Flotta (Figure 5.20: F).

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Figure 5.20: Distribution of shags recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: April / May 2012 B: May / June 2012

C: June / August 2012 D: August / September 2012

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E: October / November 2012 F: December 2012 / January 2013

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5.1.21 Grey herons

5.1.21.1 Abundance estimates

Data presented in Table 5.44 refer to grey herons. Single grey herons were recorded in the May / June 2012 and December 2012 / January 2013 survey windows within the near shore area. The relative population in May / June 2012 was estimated at 21 (1 – 61) birds.

Table 5.44 : Raw counts, number of sightings, population estimates, confidence limits and precision for grey herons in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 1 0 0 0 1 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 0 1 0 0 0 1 NSA (500 m) 0 0 1 0 0 0 1 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 0 0 1 0 0 0 1 NSA (500 m) 0 0 21 0 0 0 19 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 0 21 0 0 0 19 NSA (500 m) 0 0 1 0 0 0 1 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 1 0 0 0 1 NSA (500 m) 0 0 63 0 0 0 57 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 61 0 0 0 55 NSA (500 m) N/A N/A >1 N/A N/A N/A >1 Precision WA (2 km) N/A N/A N/A N/A N/A N/A 0 Total N/A N/A 0.22 N/A N/A N/A 0.23 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.45: Behaviour (sitting or flying) of grey herons in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 1 0 0 0 0 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 0 0 0 1 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.21.2 Distribution

In May / June 2012 survey window, a grey heron was recorded in the Bay of Isbister on the north-east coast of the Orkney Mainland (Figure 5.21: A).

During the December 2012 / January 2013 survey window, one grey heron was recorded near to the coast in the Bay of Kirkwall on the Orkney Mainland (Figure 5.21: B).

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Figure 5.21: Distribution of grey herons recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: May / June 2012 B: December 2012 / January 2013

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5.1.22 Total grebes

5.1.22.1 Abundance estimates

Data presented in Table 5.46 refer to total grebes (including Slavonian grebes and grebes that were not identified to species level). Small numbers of grebes were recorded in February / March 2012, October / November 2012 and December 2012 / January 2013. Numbers peaked in October / November when the relative population was estimated at 346 (65 – 626) birds. All grebes were recorded within the near shore area. The numbers of Slavonian grebes and grebes identified to species level is presented in Table 5.48. Relative population estimates for grebes that could be identified to species are provided in subsequent sections.

Table 5.46: Raw counts, number of sightings, population estimates, confidence limits and precision for total grebes in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 3 0 0 0 0 16 10 Count WA (2 km) 0 0 0 0 0 0 0 Total 3 0 0 0 0 16 10 NSA (500 m) 2 0 0 0 0 8 8 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 2 0 0 0 0 8 8 NSA (500 m) 60 0 0 0 0 346 189 Population WA (2 km) 0 0 0 0 0 0 0 Total 60 0 0 0 0 346 189 NSA (500 m) 3 0 0 0 0 108 76 LCL WA (2 km) 0 0 0 0 0 0 0 Total 3 0 0 0 0 65 54 NSA (500 m) 161 0 0 0 0 691 340 UCL WA (2 km) 0 0 0 0 0 0 0 Total 146 0 0 0 0 626 323 NSA (500 m) 0.58 N/A N/A N/A N/A 0.25 0.32 Precision WA (2 km) N/A N/A N/A N/A N/A N/A 0 Total 0.13 N/A N/A N/A N/A 0.05 0.07 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.47: Behaviour (sitting or flying) of total grebe species in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 3 0 0 0 0 16 10 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 0 0 0 0 Flying WA (2 km) 0 0 0 0 0 0 0

Table 5.48: Total number of grebes recorded.

Survey window Slavonian grebe Unidentified grebe Feb / Mar 2012 3 0 Apr / May 2012 0 0 May / Jun 2012 0 0 Jun / Aug 2012 0 0 Aug / Sep 2012 0 0 Oct / Nov 2012 6 10 Dec 2012 / Jan 2013 9 1

5.1.22.2 Distribution

In February / March 2012 survey window, two Slavonian grebes were recorded together in Lyrawa Bay off Hoy and one Slavonian grebe was recorded within 1 km of land in the Wide Firth off the north coast of the Orkney Mainland (Figure 5.22: A).

During the October / November 2012 survey window, moderate groups (3 – 6 birds) were recorded in Wide Firth off the north coast of the Orkney Mainland and north of the Broch of Gurness, also off mainland Orkney (Figure 5.22: B). Smaller groups (< 3) were recorded north of Langskaill, on Rousay, in the Bay of Moclett off Papa Westray, east of Cava and in Echnaloch Bay and south of Burray, both off South Ronaldsay (Figure 5.22: B)

In the December 2012 / January 2013 window, two pairs of grebes were recorded off the west coast of Vestness on Papa Westray and off the northern tip of Wyre, with individuals observed north of Shapinsay within the SPA, on the northern coast of Orkney Island, to the east of Orkney Island, in the Scapa Bay off the Orkney Mainland and north of Tongue on the Scottish Mainland (Figure 5.22: C).

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Figure 5.22: Distribution of total grebes recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: October / November 2012

C: December 2012 / January 2013

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5.1.23 Slavonian grebes

5.1.23.1 Abundance estimates

Data presented in Table 5.49 refer to Slavonian grebes. A small number of Slavonian grebes were recorded in February / March, October / November 2012 and December 2012 / January 2013 within the near shore area. Numbers peaked in December 2012 / January 2013 when the relative peak population was estimated at 170 (40 – 300) birds.

Table 5.49: Raw counts, number of sightings, population estimates, confidence limits and precision for Slavonian grebes in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 3 0 0 0 0 6 9 Count WA (2 km) 0 0 0 0 0 0 0 Total 3 0 0 0 0 6 9 NSA (500 m) 2 0 0 0 0 3 7 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 2 0 0 0 0 3 7 NSA (500 m) 60 0 0 0 0 130 170 Population WA (2 km) 0 0 0 0 0 0 0 Total 60 0 0 0 0 130 170 NSA (500 m) 3 0 0 0 0 6 57 LCL WA (2 km) 0 0 0 0 0 0 0 Total 3 0 0 0 0 6 40 NSA (500 m) 161 0 0 0 0 302 321 UCL WA (2 km) 0 0 0 0 0 0 0 Total 146 0 0 0 0 284 300 NSA (500 m) 0.58 N/A N/A N/A N/A 0.41 0.33 Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total 0.13 N/A N/A N/A N/A 0.09 0.08 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.50: Behaviour (sitting or flying) of Slavonian grebes in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 3 0 0 0 0 6 9 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 0 0 0 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.23.2 Distribution

During the October / November 2012 survey window, six Slavonian grebes were recorded in three groups, with the largest group (3 – 6 birds) recorded within the Wide Firth off the north coast of Orkney Mainland, an individual Slavonian grebe was also located in Wide Firth closer to land. A pair of Slavonian grebes was also recorded north of Burray within Echnaloch Bay (Figure 5.23: B).

In the December 2012 / January 2013 window, small groups of Slavonian grebes were recorded off the west coast of Vestness on Papa Westray and off the northern tip of Wyre, with individuals observed on the northern coast of Orkney Island, to the east of Orkney Island, in the north of Fersness Bay on Eday, in the Scapa Bay off the Orkney Mainland and north of Tongue on the Scottish Mainland (Figure 5.22: C).

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Figure 5.23: Distribution of Slavonian grebes recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: October / November 2012

C: December 2012 / January 2013 98

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5.1.24 Total waders

5.1.24.1 Abundance estimates

Data presented in Table 5.51 refer to total waders (including oystercatchers, lapwings, curlews and waders not identified to species level). Small to moderate numbers of waders were recorded in all survey windows. Numbers peaked in February / March 2012 when the relative population was estimated at 10,395 (518 – 22,956) birds. The vast majority of waders were recorded within the near shore area; one wader was recorded in the wider area in April / May 2012 and December 2012 / January 2013. The numbers of waders identified to species level is presented in Table 5.53. Relative population estimates for waders that could be identified to species are provided in subsequent sections.

Table 5.51: Raw counts, number of sightings, population estimates, confidence limits and precision for total waders in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 518 106 32 4 8 93 394 Count WA (2 km) 0 1 0 0 0 0 1 Total 518 107 32 4 8 93 395 NSA (500 m) 11 9 7 4 2 3 14 Number of WA (2 km) 0 1 0 0 0 0 1 sightings Total 11 10 7 4 2 3 15 NSA (500 m) 10,395 2,056 675 98 246 2,009 7,439 Population WA (2 km) 0 79 0 0 0 0 105 Total 10,395 2,136 675 98 246 2,009 7,544 NSA (500 m) 518 106 84 24 8 93 1,473 LCL WA (2 km) 0 1 0 0 0 0 1 Total 518 107 32 4 8 93 395 NSA (500 m) 25,065 4,617 1,603 195 646 5,011 17,069 UCL WA (2 km) 0 238 0 0 0 0 314 Total 22,956 4,302 1,490 191 591 4,698 15,279 NSA (500 m) 0.04 0.10 0.18 0.5 0.35 0.1 0.05 Precision WA (2 km) N/A >1 N/A N/A N/A N/A >1 Total 0.01 0.02 0.04 0.1 0.06 0.02 0.01 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.52: Behaviour (sitting or flying) of total waders in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 3 2 1 0 0 10 59 Sitting WA (2 km) 0 1 0 0 0 0 0 NSA (500 m) 515 104 31 4 8 83 335 Flying WA (2 km) 0 0 0 0 0 0 1

Table 5.53: Total number of each species of wader recorded.

Survey window Oystercatchers Lapwings Curlews Unidentified waders Feb / Mar 2012 76 0 439 3 Apr / May 2012 3 0 26 78 May / Jun 2012 8 0 5 19 Jun / Aug 2012 0 0 4 0 Aug / Sep 2012 8 0 0 0 Oct / Nov 2012 0 45 1 47 Dec 2012 / Jan 2013 9 69 231 86

5.1.24.2 Distribution

In February / March 2012, relatively large groups of waders (>31 individuals) were recorded in the Bay of Ireland and in the Bay of Sandoyne on the southern coast of Orkney Mainland and in the Bay of Firth on the northern coast of Orkney Mainland (Figure 5.24: A). A smaller aggregation of waders was recorded off Herston on South Ronaldsay, with single waders scattered throughout the Orkney archipelagos (Figure 5.24: A).

In April / May 2012, clusters of waders were recorded off the eastern tip of Burray, between Hoy and Rysa Little and on Orkney Mainland in the Bay of Berstane and to the west of Stromness (Figure 5.18: B). Further individuals were scattered around the coasts of Orkney Mainland and Graemsay (Figure 5.24: B).

During the May / June 2012 survey window, wader numbers were reduced but a similar distribution was recorded to the April / May 2012 survey window with a high concentration of waders located off the east of Burray (Figure 5.24: C).

In June / August 2012, wader numbers had greatly reduced compared to those observed earlier in the year, with four birds recorded to the north of Egilsay, the north of Burray and in Thurso Bay and Torrisdale Bay along the northern coast of the Scottish mainland (Figure 5.24: D).

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In August / September 2012, two small groups (3 – 6 birds) were recorded in the south-west of the PFOW survey area, east of Durness and within the Kyle of Tongue along the coast of the Scottish mainland (Figure 5.24: E).

During the October / November 2012 survey, two large groups(< 31 birds) were recorded off the Point of Backaquoy on the Orkney Mainland and close to St Peter’s Bay also off the Orkney Mainland (Figure 5.24: F).

During the December 2012 / January 2013 survey, wader numbers increased compared to the previous survey window, with large groups of 11 – 30 and + 31 birds recorded off Bow head off Westray, north of Quarry on Eday, in the Bay of Isbister, Bay of Ireland on the Orkney Mainland and south of Stonehall also on the Orkney Mainland, in Long Hope north of South Walls and in Weddel Sound between Fara and Flotta (Figure 5.24: G).

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Figure 5.24: Distribution of total waders recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.25 Oystercatchers

5.1.25.1 Abundance estimates

Data presented in Table 5.54 refer to oystercatchers. Small numbers of oystercatchers were recorded in all survey windows except June / August and October / November 2012. Numbers peaked in February / March 2012 when the relative population was estimated at 1,525 (76 – 4,173) birds. All oystercatchers were recorded within the near shore area.

Table 5.54: Raw counts, number of sightings, population estimates, confidence limits and precision for oystercatchers in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 76 3 8 0 8 0 9 Count WA (2 km) 0 0 0 0 0 0 0 Total 76 3 8 0 8 0 9 NSA (500 m) 7 3 2 0 2 0 0 Number of WA (2 km) 0 0 0 0 0 0 0 sighting Total 7 3 2 0 2 0 0 NSA (500 m) 1,525 58 169 0 246 0 170 Population WA (2 km) 0 0 0 0 0 0 0 Total 1,525 58 169 0 246 0 170 NSA (500 m) 76 3 8 0 8 0 9 LCL WA (2 km) 0 0 0 0 0 0 0 Total 76 3 8 0 8 0 9 NSA (500 m) 4,375 136 464 0 646 0 604 UCL WA (2 km) 0 0 0 0 0 0 0 Total 4,173 122 424 0 591 0 460 NSA (500 m) 0.11 0.58 0.35 N/A 0.35 N/A 0.33 Precision WA (2 km) N/A N/A N/A N/A 0 N/A 0 Total 0.03 0.13 0.08 N/A N/A 0.08 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.55: Behaviour (sitting or flying) of oystercatchers in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 0 0 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 76 3 8 0 8 0 9 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.25.2 Distribution

In February / March 2012, a large cluster of oystercatchers were recorded within the Bay of Firth on the northern coast of Orkney Mainland. Groups of one or two birds were located in the Bay of Kirkwall on Orkney Mainland, south of Westray, west of Papa Westray, east of Rousay, off the north-western tip of Hoy and off the north-eastern tip of the Scottish mainland during this survey window (Figure 5.25: A).

In April / May 2012, three oystercatchers were recorded; one in Thurso Bay on the Scottish mainland, one in the Bay of Firth on Orkney Mainland and one off the eastern coast of Eday (Figure 5.25: B).

In May / June 2012, oystercatchers were clustered in two groups; one group was located off the western coast of Hoy, opposite Flotta and the other was recorded in the Bay of Berstane on the northern coast of Orkney Mainland (Figure 5.25: C).

During the December 2012 / January 2013 survey window, a group (7 – 10 birds) was recorded north of Brough on the coast of the Scottish Mainland, with a single oystercatcher observed north of South Ronaldsay in Water Sound (Figure 5.25: E).

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Figure 5.25: Distribution of oystercatchers recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: August / September 2012

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E: December 2012 / January 2013

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5.1.26 Lapwings

5.1.26.1 Abundance estimates

Data presented in Table 5.56 refer to Lapwings. Moderate numbers of Lapwings were recorded in the October / November 2012 and December 2012 / January 2013 survey windows within the near shore area. The relative population peaked in December 2012 / January 2013 when the relative population was estimated at 1,303 (69 – 3,788) birds.

Table 5.56: Raw counts, number of sightings, population estimates, confidence limits and precision for lapwings in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 45 69 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 45 69 NSA (500 m) 0 0 0 0 0 1 1 Number of WA (2 km) 0 0 0 0 0 0 0 sighting Total 0 0 0 0 0 1 1 NSA (500 m) 0 0 0 0 0 972 1,303 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 972 1,303 NSA (500 m) 0 0 0 0 0 45 69 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 45 69 NSA (500 m) 0 0 0 0 0 2,916 3,908 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 0 2,832 3,788 NSA (500 m) N/A N/A N/A N/A N/A 0.15 0.12 Precision WA (2 km) N/A N/A N/A N/A N/A N/A 0 Total N/A N/A N/A N/A N/A 0.03 0.03 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.57: Behaviour (sitting or flying) of lapwings in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 3 2 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 0 0 42 67 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.26.2 Distribution

During the October / November 2012 survey window, a large group (+ 31 birds) were recorded east of Deerness close to the mouth of St Peter’s Pool, off the coast of the Orkney Mainland (Figure 5.26: A).

Peak numbers of lapwings were recorded during the December 2012 / January 2013 survey window, with 69 lapwings observed together in Long Hope between Hoy and South Walls (Figure 5.26: B).

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Figure 5.26: Distribution of lapwings recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: October / November 2012 B: December 2012 / January 2013

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5.1.27 Curlews

5.1.27.1 Abundance estimates

Data presented in Table 5.58 refer to curlews. Small numbers of curlews were recorded in all survey windows except August / September 2012. Numbers peaked in February / March 2012 when the relative population was estimated at 8,810 (439 – 21,082) birds. All curlews were recorded within the near shore area.

Table 5.58: Raw counts, number of sightings, population estimates, confidence limits and precision for curlews in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct 2012 / Mar May Jun Aug Sep /Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 439 26 5 4 0 1 231 Count WA (2 km) 0 0 0 0 0 0 0 Total 439 26 5 4 0 1 231 NSA (500 m) 5 2 4 4 0 1 9 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 5 2 4 4 0 1 9 NSA (500 m) 8,810 504 105 98 0 22 4,362 Population WA (2 km) 0 0 0 0 0 0 0 Total 8,810 504 105 98 0 22 4,362 NSA (500 m) 439 26 21 24 0 1 321 LCL WA (2 km) 0 0 0 0 0 0 0 Total 439 26 5 4 0 1 231 NSA (500 m) 23,178 1,474 232 219 0 65 10,668 UCL WA (2 km) 0 0 0 0 0 0 0 Total 21,082 1,396 212 191 0 63 9,593 NSA (500 m) 0.05 0.20 0.45 0.5 N/A >1 0.07 Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total 0.01 0.04 0.1 0.1 N/A 0.22 0.02 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.59: Behaviour (sitting or flying) of curlews in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 1 0 0 0 0 7 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 439 25 5 4 0 1 224 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.27.2 Distribution

In February / March 2012, two large aggregations of curlews were recorded; one was located in the Bay of Sandoyne and the other in the Bay of Ireland, both of which are on the southern coast of Orkney Mainland (Figure 5.27: A). Individual curlews were recorded in the Bay of Firth on Orkney Mainland, off the southern coast of Wyre and off Herston on South Ronaldsay during this survey (Figure 5.27: A).

In April / May 2012, a large cluster of curlews were recorded off the eastern coast of Burray with a smaller group if individuals located off Rapness on the southern coast of Westray (Figure 5.27: B).

In May / June 2012, curlews were scattered around the coast of Orkney Mainland and off the south-eastern tip of Graemsay (Figure 5.27: C).

During the June / July 2012 survey window, four curlews were recorded and these were located to the north of Egilsay, the north of Burray and in Thurso Bay and Torrisdale Bay along the northern coast of the Scottish mainland (Figure 5.27: D).

In October / November 2012 one curlew was recorded east of Deerness close to the coast of the Orkney Mainland (Figure 5.27 E).

During the December 2012 / January 2013 survey window, the largest group ( +31 birds) was recorded in Ferness Bay off Eday, with large groups (11 – 30 birds) observed in the Bay of Isbister and south of Stonehall off the Orkney Mainland and within Long Hope between Hoy and South Walls (Figure 5.27:F).

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Figure 5.27: Distribution of curlews recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: October / November 2012 F: December 2012 / January 2013

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5.1.28 Total skuas

5.1.28.1 Abundance estimates

Data presented in Table 5.60 refer to total skuas (including Arctic skuas and great skuas. Small numbers of skuas were recorded in May / June 2012, June / August 2012 and August / September 2012. Numbers peaked in June / August 2012 when the relative population was estimated at 960 (542 – 1,377) birds. Skuas were recorded both within the near shore area and wider area. The numbers of skuas identified to species level is presented in Table 5.62. Relative population estimates for skuas that could be identified to species are provided in subsequent sections.

Table 5.60: Raw counts, number of sightings, population estimates, confidence limits and precision for total skuas in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 5 25 15 0 0 Count WA (2 km) 0 0 0 4 3 0 0 Total 0 0 5 29 18 0 0 NSA (500 m) 0 0 5 24 14 0 0 Number of WA (2 km) 0 0 0 4 3 0 0 sightings Total 0 0 5 28 17 0 0 NSA (500 m) 0 0 105 609 461 0 0 Population WA (2 km) 0 0 0 350 339 0 0 Total 0 0 105 960 800 0 0 NSA (500 m) 0 0 21 390 215 0 0 LCL WA (2 km) 0 0 0 88 3 0 0 Total 0 0 15 542 347 0 0 NSA (500 m) 0 0 211 878 707 0 0 UCL WA (2 km) 0 0 0 700 791 0 0 Total 0 0 196 1,377 1,253 0 0 NSA (500 m) N/A N/A 0.45 0.2 0.26 N/A N/A Precision WA (2 km) N/A N/A N/A 0.5 0.58 N/A N/A Total N/A N/A 0.1 0.03 0.04 N/A N/A Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.61: Behaviour (sitting or flying) of total skuas in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 1 0 0 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 5 25 14 0 0 Flying WA (2 km) 0 0 0 4 3 0 0

Table 5.62: Total number of each species of skua recorded.

Survey window Arctic skua Great skua Feb / Mar 2012 0 0 Apr / May 2012 0 0 May / Jun 2012 0 5 Jun / Aug 2012 0 29 Aug / Sep 2012 2 16 Oct / Nov 2012 0 0 Dec 2012 / Jan 2013 0 0

5.1.28.2 Distribution

In May / June 2012 survey window, five great skuas were recorded; two individuals were recorded off Duncansby Head on the Scottish mainland with a further two individuals recorded further west along the northern coast of the Scottish mainland. The fifth great skua was located off the eastern coast of Hoy, within Bring Deeps (Figure 5.28: A).

In June / August survey window, the number of great skuas recorded had increased since the last survey, with single individuals scattered along the western coasts of Orkney Mainland and Hoy, within Scapa Flow, around the coasts of Westray and Eday and off the north- eastern tip of the Scottish mainland (Figure 5.28: B).

During the August / September 2012 survey, small groups and individual skuas were thinly distributed throughout the Orkney Islands from Lashy Sound between Eday and Sanday to north of Tongue, off the Scottish mainland (Figure 5.28: C).Multiple small groups of skuas were recorded south of Kirkwall, within Scapa Bay and the surrounding waters between the south coast of the Orkney Mainland, north of South Ronaldsay and east of Hoy (Figure 5.28: C).

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Figure 5.28: Distribution of total skuas recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: May / June 2012 B: June / August 2012

C: August / September 2012

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5.1.29 Arctic Skuas

5.1.29.1 Abundance estimates

Data presented in Table 5.63 refer to Arctic skuas. Small numbers of Arctic skuas were recorded in August / September 2012 when the relative population was estimated at 61 (2 – 145) birds. All Arctic skuas were recorded within the near shore area.

Table 5.63: Raw counts, number of sightings, population estimates, confidence limits and precision for Arctic skuas in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 2 0 0 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 2 0 0 NSA (500 m) 0 0 0 0 2 0 0 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 0 0 0 0 2 0 0 NSA (500 m) 0 0 0 0 61 0 0 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 61 0 0 NSA (500 m) 0 0 0 0 2 0 0 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 2 0 0 NSA (500 m) 0 0 0 0 154 0 0 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 145 0 0 NSA (500 m) N/A N/A N/A N/A 0.71 N/A N/A Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total N/A N/A N/A N/A 0.13 N/A N/A Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.64: Behaviour (sitting or flying) of Arctic skuas in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 1 0 0 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 0 1 0 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.29.2 Distribution

During the August / September 2012 survey window, two Arctic skuas were both recorded less than 3 km from land, to the west of Hoy and west of Guith off the west coast of Eday (Figure 5.29:A).

Figure 5.29: Distribution of Arctic skuas recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: August / September 2012

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5.1.30 Great Skuas

5.1.30.1 Abundance estimates

Data presented in Table 5.65 refer to great skuas. Small numbers of great skuas were recorded in May / June and June / August 2012. Numbers peaked in June / August 2012 when the relative population was estimated at 960 (542 – 1,377) birds. The majority of great skuas were recorded within the near shore area; four great skuas were recorded in the wider area in June / August 2012 and three in the wider area in August / September 2012.

Table 5.65: Raw counts, number of sightings, population estimates, confidence limits and precision for great skuas in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 5 25 13 0 0 Count WA (2 km) 0 0 0 4 3 0 0 Total 0 0 5 29 16 0 0 NSA (500 m) 0 0 5 24 12 0 0 Number of WA (2 km) 0 0 0 4 3 0 0 sightings Total 0 0 5 28 15 0 0 NSA (500 m) 0 0 105 609 400 0 0 Population WA (2 km) 0 0 0 350 339 0 0 Total 0 0 105 960 738 0 0 NSA (500 m) 0 0 21 390 184 0 0 LCL WA (2 km) 0 0 0 88 3 0 0 Total 0 0 15 542 294 0 0 NSA (500 m) 0 0 211 878 646 0 0 UCL WA (2 km) 0 0 0 700 791 0 0 Total 0 0 196 1,377 1,183 0 0 NSA (500 m) N/A N/A 0.45 0.2 0.28 N/A N/A Precision WA (2 km) N/A N/A N/A 0.5 0.58 N/A N/A Total N/A N/A 0.1 0.03 0.04 N/A N/A Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.66: Behaviour (sitting or flying) of great skuas in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 0 0 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 5 25 13 0 0 Flying WA (2 km) 0 0 0 4 3 0 0

5.1.30.2 Distribution

During the August / September 2012 survey small groups and individual skuas were thinly distributed throughout the Orkney Islands from Lashy Sound between Eday and Sanday to north of Tongue, off the Scottish Mainland (Figure 5.30: C). Multiple small groups of skuas were recorded south of Kirkwall, within Scapa Bay and the surrounding waters between the south coast of the Orkney mainland, north of South Ronaldsay and east of Hoy (Figure 5.30: C).

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Figure 5.30: Distribution of great skuas recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: May / June 2012 B: June / August 2012

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5.1.31 Total small gulls

5.1.31.1 Abundance estimates

Data presented in Table 5.67 refer to total small gulls (including kittiwakes, black-headed gulls, common gulls and small gulls not identified to species level). Moderate numbers of small gulls were recorded in all survey windows. Numbers peaked in October / November 2012 when the relative population was estimated at 16,239 (11,026 – 21,451) birds. Small gulls were recorded within the near shore area and wider area, although the majority were recorded within the near shore area. The numbers of small gulls identified to species level is presented in Table 5.69. Relative population estimates for small gulls that could be identified to species are provided in subsequent sections

Table 5.67: Raw counts, number of sightings, population estimates, confidence limits and precision for total small gulls in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 276 346 345 541 154 564 493 Count WA (2 km) 55 8 7 20 17 47 16 Total 331 354 352 561 171 611 509 NSA (500 m) 85 56 89 160 82 185 81 Number of WA (2 km) 17 8 6 17 14 35 16 sightings Total 102 64 95 177 96 220 97 NSA (500 m) 5,539 6,712 7,276 13,188 4,734 12,182 9,309 Population WA (2 km) 4,816 635 658 1,751 1,920 4,056 1,673 Total 10,354 7,348 7,935 14,939 6,654 16,239 10,982 NSA (500 m) 3,391 2,464 4,092 7,337 3,320 7,776 3,399 LCL WA (2 km) 1,138 238 188 875 1,017 2,675 941 Total 4,152 1,759 4,658 7,525 4,628 11,026 4,273 NSA (500 m) 8,308 13,890 10,799 22,329 6,609 17,755 17,163 UCL WA (2 km) 11,470 1,112 1,317 2,626 3,163 5,782 2,509 Total 16,556 12,936 11,211 22,352 8,680 21,451 17,690 NSA (500 m) 0.06 0.05 0.05 0.04 0.08 0.04 0.05 Precision WA (2 km) 0.13 0.35 0.38 0.22 0.24 0.15 0.25 Total 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.68: Behaviour (sitting or flying) of total small gulls in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 145 57 122 183 31 278 121 Sitting WA (2 km) 15 1 4 8 9 12 2 NSA (500 m) 131 289 223 358 123 286 373 Flying WA (2 km) 40 7 3 12 8 35 14

Table 5.69: Total number of each species of small gull recorded.

Black- Common Unidentified Survey window Kittiwake headed gull gull small gulls Feb / Mar 2012 111 3 130 87 Apr / May 2012 277 7 43 27 May / Jun 2012 283 4 26 39 Jun / Aug 2012 455 0 22 84 Aug / Sep 2012 148 8 5 10 Oct / Nov 2012 165 18 349 79 Dec 2012 / Jan 2013 33 79 356 41

5.1.31.2 Distribution

In February / March 2012, small gulls were recorded throughout the PFOW survey area, although few were recorded in the far west of the site (Figure 5.31: A). High concentrations of small gulls were located to the south of Westray, off the western coast, particularly Marwick Head, on Orkney Mainland, and within the Bay of Kirkwall and Bay of Ireland, also on Orkney Mainland (Figure 5.31: A).

In April / May 2012, small gulls were less dispersed compared with the previous survey with the largest aggregations of birds located along the northern coast of the Scottish mainland (Figure 5.31: B). Smaller groups of small gulls were recorded off Noup Head on Westray, off the south-eastern tip of Eday, along the north-western coast of Orkney Mainland and in Scapa Bay on Orkney Mainland and off the western coast of Hoy (Figure 5.31: B).

During the May / June 2012 survey window, small gulls were strongly associated with coastal areas with few birds recorded further offshore (Figure 5.31: C). The largest clusters of small gulls were recorded off Noup Head on Westray, to the north of Shapinsay in the Stronsay Firth, in the Bay of Isbister on Orkney Mainland, off Brims Ness on the south coat of Hoy and along the northern coast of the Scottish mainland (Figure 5.31: C).

During the June / August 2012 survey window, a similar distribution was observed, although small gulls were recorded in smaller clusters that during the previous survey window (Figure 5.31: D). The highest concentrations of small gulls were recorded off Noup Head on Westray, 124

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In August / September 2012, decreased numbers of small gulls were recorded with the majority of birds recorded sitting on the sea surface, with an increase in the number of small gulls observed in open water compared to the previous survey window (Figure 5.31: E). The highest concentrations of small gulls were recorded in the Bay of Ham off the west coast of Rousay, off the south-west tip of Eday near the Bay of Greentoft and north of Sandside Bay off the Scottish mainland (Figure 5.31:E).

In October / November 2012, small gulls were recorded throughout the PFOW survey area, with an increase in small gulls recorded further offshore in the north-west of the survey area. High concentrations of small gulls were recorded east of Burray on South Ronaldsay, in Scapa Flow and the Bay of Firth off the Orkney Mainland and off Mirkady Point also on the Orkney Mainland (Figure 5.31:F).

In December 2012 / January 2013, small gull numbers decreased compared to the previous survey month with the majority of birds observed flying in the near shore area. Large groups ( +31 birds) were recorded in the Bay of Backaland on Eday, off the Point of Ayre on the Orkney Mainland, on the south coast of Flotta and north of John o’ Groats off the Scottish mainland (Figure 5.31: G).

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Figure 5.31: Distribution of total small gulls recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.32 Kittiwakes

5.1.32.1 Abundance estimates

Data presented in Table 5.70 refer to kittiwakes. Generally kittiwakes were the most abundant species of small gulls recorded in the PFOW area (Table 5.69) and moderate numbers of kittiwakes were recorded in all survey windows. Numbers peaked in June / August 2012 when the relative population was estimated at 11,976 (4,606 – 19,345) birds. Kittiwakes were recorded within the near shore area and wider area.

Table 5.70: Raw counts, number of sightings, population estimates, confidence limits and precision for kittiwakes in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 65 270 278 441 133 125 24 Count WA (2 km) 46 7 5 14 15 40 9 Total 111 277 283 455 148 165 33 NSA (500 m) 34 26 64 100 68 78 20 Number of WA (2 km) 11 7 4 12 12 29 9 sightings Total 45 33 68 112 80 107 29 NSA (500 m) 1,304 5,238 5,863 10,750 4,088 2,700 453 Population WA (2 km) 4,028 556 470 1,226 1,694 3,452 941 Total 5,332 5,794 6,334 11,976 5,783 6,152 1,394 NSA (500 m) 783 989 2,995 5,022 2,613 1,966 245 LCL WA (2 km) 613 159 94 613 678 2,158 418 Total 111 277 3,218 4,606 3816 4,603 750 NSA (500 m) 1,927 11,310 9,217 19,038 6,025 3,521 680 UCL WA (2 km) 10,244 953 1,034 2,014 2,824 4,833 1,568 Total 11,038 11,344 9,449 19,345 7750 7,701 2,039 NSA (500 m) 0.12 0.06 0.06 0.05 0.09 0.09 0.2 Precision WA (2 km) 0.15 0.38 0.45 0.27 0.26 0.16 0.33 Total 0.01 0.01 0.01 0.01 0.01 0.01 0.03 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.71: Behaviour (sitting or flying) of kittiwakes in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 29 234 75 141 25 39 5 Sitting WA (2 km) 13 1 2 5 9 8 0 NSA (500 m) 36 36 203 300 108 86 19 Flying WA (2 km) 33 6 3 9 6 32 9

5.1.32.2 Distribution

During the February / March 2012 survey window, kittiwakes were recorded throughout much of the PFOW survey area (Figure 5.32: A). Higher numbers of kittiwakes were noted around the coast of Westray and Papa Westray and along the northern coast of Orkney Mainland (Figure 5.32: A).

In April / May 2012, kittiwakes were more concentrated with large clusters of individuals recorded along the northern coast of the Scottish mainland (Figure 5.32: B). Smaller concentrations of kittiwakes were recorded within Deer Sound on Orkney Mainland, off Noup Head on Westray and in the Bay of Tuquoy on the southern coast of Westray (Figure 5.32: B).

In May / June 2012, large clusters of kittiwakes were again recorded along the northern coast of mainland Scotland, off Noup Head on Westray, off Brims Ness on the south of Orkney Mainland and to the north of Shapinsay within the Stronsay Firth (Figure 5.32: C). However, the distribution of kittiwakes during this survey window appeared to become more fragmented, with smaller groups of individuals recorded along the northern coast of Scotland in particular (Figure 5.32: C).

In June / August 2012, high number of kittiwakes were recorded around Duncansby Head, Spear Head and the Kyle of Tongue along the northern coast of Scotland (Figure 5.32: D), whilst within the Orkney archipelagos, high numbers of kittiwakes were recorded around Noup Head and the west of Westray, within Gairsay Sound and Wide Firth and on the eastern boundary of the PFOW survey area (Figure 5.32: D).

During the August / September 2012 survey window, kittiwakes were recorded off Duncansby Head and north of Reay along mainland Scotland (Figure 5.23:E), with large groups (7 – 10 birds) recorded off War Ness on Eday, in the Bay of Ham on Rousay and south of Avalsay also on Rousay. Smaller clusters of kittiwakes were also recorded along the coastlines of South Ronaldsay, Westray, Shapinsay and east of Flotta with individual kittiwakes recorded in open water to the north and east of the PFOW survey area (Figure 5.32: E).

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In October / November 2012 high concentrations of kittiwakes were recorded in the north- west of the PFOW survey area, with increased numbers of kittiwakes recorded in open water compared to previous survey windows (Figure 5.32: F). Larger groups of kittiwakes were recorded off Brough Head on the Orkney Mainland, in the Bay of London and Eday Sound off the east coast of Eday and north of Papa Westray (Figure 5.32: F).

During the December 2012 / January 2013 survey window, numbers of kittiwakes decreased compared to previous survey windows, with the largest group ( 3- 6 birds) recorded north of Ham along the Scottish Mainland. Single kittiwakes were observed close to the coast off the west coast of Westray, north of Rousay, on the west and south coast of the Orkney Mainland, to the west of Hoy and in open water to the north of Papa Westray and north of the Scottish mainland, with individuals observed in the far south-west of the survey area (Figure 5.32: G).

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Figure 5.32: Distribution of kittiwakes recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November

G: December 2012 / January 2013

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5.1.33 Black-headed gulls

5.1.33.1 Abundance estimates

Data presented in Table 5.72 refer to black-headed gulls. Black-headed gulls were the least abundant species of small gull recorded in the PFOW area (Table 5.69). Low numbers were recorded in all survey windows except June / August. Numbers peaked in December 2012 / January 2013 when the relative population was estimated at 1,577 (79 – 4,013) birds. All black-headed gulls were recorded within the near shore area except in August / September 2012 and December 2012 / January 2013 when birds were also recorded in the wider area.

Table 5.72: Raw counts, number of sightings, population estimates, confidence limits and precision for black-headed gulls in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 3 7 4 0 7 18 78 Count WA (2 km) 0 0 0 0 1 0 1 Total 3 7 4 0 8 18 79 NSA (500 m) 2 5 4 0 4 6 5 Number of WA (2 km) 0 0 0 0 1 0 1 sightings Total 2 5 4 0 5 6 6 NSA (500 m) 60 136 84 0 215 389 1,473 Population WA (2 km) 0 0 0 0 113 0 105 Total 60 136 84 0 328 389 1,577 NSA (500 m) 3 19 21 0 31 86 78 LCL WA (2 km) 0 0 0 0 1 0 1 Total 3 13 4 0 8 43 79 NSA (500 m) 161 272 169 0 523 778 4,211 UCL WA (2 km) 0 0 0 0 339 0 314 Total 146 259 165 0 668 734 4,013 NSA (500 m) 0.58 0.38 0.50 N/A 0.38 0.24 0.11 Precision WA (2 km) N/A N/A N/A N/A >1 N/A >1 Total 0.13 0.09 0.11 N/A 0.06 0.05 0.03 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.73: Behaviour (sitting or flying) black-headed gulls in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 1 0 0 11 53 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 3 7 3 0 7 7 25 Flying WA (2 km) 0 0 0 0 1 0 1

5.1.33.2 Distribution

In February / March 2012, two black-headed gulls were recorded < 1 km from shore in the Bay of Ireland south of the Orkney Mainland; another individual was recorded off Graemsay in Hoy Sound (Figure 5.33: A).

In April / May 2012, small groups (1-2 birds) were recorded close to shore around the Orkney Mainland and one individual was recorded in the Bay of Backaland off Eday (Figure 5.33: B).

In May / June 2012, four single sightings of black- headed gulls were recorded scattered between the Bay of Isbister off the Orkney Mainland to Dunnet Bay off the north coast of Scotland (Figure 5.33: C).

During the August / September 2012 survey window, a moderate group (3 – 6 birds) was recorded north of Work on the coast of the Orkney Mainland, with four individual black- headed gulls recorded north of Dounreay and east of Spear Head off the Scottish mainland (Figure 5.33: D).

In October / November 2012, an increased number of black-headed gulls were recorded around the coast of the Orkney Mainland, north of Kirkwall, in the Bay of Isbister, in Scapa Flow, in Taracliff Bay and west of Gritley also on the Orkney Mainland. A small group of black-headed gulls was also recorded north of Hoxa on South Ronaldsay (Figure 5.33: E).

During the December 2012 / January 2013 survey window, the majority of black-headed gulls were recorded along the coast of the Scottish mainland north of John o’ Groats, with a smaller group (7 – 10 birds) observed in Scapa Bay off the south coast of the Orkney Mainland. A pair of black-headed gulls were also observed off the south coast of Flotta, with single gulls recorded on the south-east coast of South Ronaldsay, to the east of Graemsay and in open water to the west of the Orkney Mainland (Figure 5.33:F).

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Figure 5.33: Distribution of black-headed gulls recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: August / September 2012

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E: October / November 2012 F: December 2012 / January 2013

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5.1.34 Common gulls

5.1.34.1 Abundance estimates

Data presented in Table 5.74 refer to common gulls. Low to moderate numbers of common gulls were recorded in all survey windows. Numbers peaked in October / November 2012 when the relative population was estimated at 7,668 (3,064 – 12,271). Common gulls were recorded both within the near shore area and wider area, although the estimated relative population was higher within the near shore area in all survey windows.

Table 5.74: Raw counts, number of sightings, population estimates, confidence limits and precision for common gulls in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 125 42 26 22 5 347 356 Count WA (2 km) 5 1 0 0 0 2 0 Total 130 43 26 22 5 349 356 NSA (500 m) 24 20 7 15 5 89 44 Number of WA (2 km) 2 1 0 0 0 2 0 sightings Total 26 21 7 15 5 91 44 NSA (500 m) 2,508 815 548 536 154 7,495 6,722 Population WA (2 km) 438 79 0 0 0 173 0 Total 2,946 894 548 536 154 7,668 6,722 NSA (500 m) 963 446 63 244 31 3,629 1,511 LCL WA (2 km) 5 1 0 0 0 2 0 Total 951 449 26 234 21 3,064 669 NSA (500 m) 4,856 1,300 1,455 902 307 13,305 14,369 UCL WA (2 km) 1,138 238 0 0 0 432 0 Total 4,942 1,340 1,361 839 286 12,271 12,775 NSA (500 m) 0.09 0.15 0.20 0.21 0.45 0.05 0.05 Precision WA (2 km) 0.45 >1 N/A N/A N/A 0.71 0 Total 0.02 0.03 0.04 0.04 0.08 0.01 0.01 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.75: Behaviour (sitting or flying) of common gulls in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar20 May Jun Aug /Sep Nov Jan 12 2012 2012 2012 2012 2012 2013 NSA (500 m) 63 1 19 0 0 179 42 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 62 41 7 22 5 168 314 Flying WA (2 km) 5 1 0 0 0 2 0

5.1.34.2 Distribution

In February / March 2012, common gulls were scattered close to the coast around the survey area from Westray in the north of the site to Scarfskerry Point in the south. Two large groups (11 – 30 birds) were recorded around the Orkney Mainland off Haafs Hellia and in the Bay of Ireland in this first survey window (Figure 5.34: A).

During the April / May 2012 survey window, several small groups of common gulls (largest group 6 birds) were distributed between the Isle of Eday in the north of the site to Thurso Bay off mainland Scotland in the south (Figure 5.34: B).

During the May / June 2012 survey window, a large group (11 – 30 birds) of common gulls was recorded in the Bay of Isbister off Mainland Orkney while single birds were recorded around other parts of the Orkney Mainland, Rousay and South Ronaldsay (Figure 5.34: C).

In June / August 2012 survey window, a group of 3-6 common gulls was recorded within the Bay of Hinderayre of the north-west coast of Orkney Mainland (Figure 5.34: D). Further, single individuals or groups of two birds were located along the northern coasts of Rousay, Westray, Egilsay and Burray and off Herston on the western coast of South Ronaldsay (Figure 5.34: D).

In the August / September 2012, individual common gulls were recorded north of Northtown off the coast of South Ronaldsay, close to Berst Ness off Westray and along the west coast of Eday in Fersness Bay, with the remaining two individuals recorded within the Wide Firth and north of Kirkwall on the Orkney Mainland (Figure 5.34: E).

During the October / November 2012 survey window, common gulls were recorded throughout much of the PFOW survey area (Figure 5.34: F). Large groups (+31 birds) were noted around the coast of the Orkney Mainland in the Bay of Firth and east of Mirkady Point as well as on the east coast of Burray (Figure 5.34: F).

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Figure 5.34: Distribution of common gulls recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.35 Total large gulls

5.1.35.1 Abundance estimates

Data presented in Table 5.76 refer to total large gulls (including lesser black-backed gulls, herring gulls, great black-backed gulls and large gulls not identified to species level). Moderate numbers of large gulls were recorded in all survey windows. Numbers peaked in February / March 2012 when the relative population was estimated at 10,816 (6,672 – 14,961) birds. Large gulls were recorded within the near shore area and wider area, although the majority were recorded within the near shore area in each survey window. The numbers of large gulls identified to species level is presented in Table 5.78. Relative population estimates for large gulls that could be identified to species are provided in subsequent sections.

Table 5.76: Raw counts, number of sightings, population estimates, confidence limits and precision for total large gulls in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 491 155 109 183 30 281 249 Count WA (2 km) 11 4 3 13 3 14 5 Total 502 159 112 196 33 295 254 NSA (500 m) 133 72 54 92 26 115 105 Number of WA (2 km) 9 3 3 12 3 9 5 sightings Total 142 75 57 104 29 124 110 NSA (500 m) 9,853 3,007 2,299 4,461 922 6,070 4,702 Population WA (2 km) 963 318 282 1,138 339 1,208 523 Total 10,816 3,325 2,581 5,599 1,261 7,278 5,224 NSA (500 m) 6,321 1,921 1,329 2,730 584 3,780 2,776 LCL WA (2 km) 350 4 3 525 3 345 105 Total 6,672 2,136 1,283 3,425 728 4,319 3,013 NSA (500 m) 14,308 4,190 3,944 6,874 1,322 9,439 7,213 UCL WA (2 km) 1,576 794 564 1,838 791 2,330 1,046 Total 14,961 4,513 3,879 7,773 1,794 10,237 7,436 NSA (500 m) 0.05 0.08 0.10 0.07 0.18 0.06 0.06 Precision WA (2 km) 0.30 0.50 0.58 0.28 0.58 0.27 0.45 Total 0.01 0.02 0.02 0.01 0.03 0.01 0.01 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.77: Behaviour (sitting or flying) of total large gulls in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 381 110 85 146 17 219 118 Sitting WA (2 km) 11 3 3 12 3 10 2 NSA (500 m) 110 45 24 37 13 62 131 Flying WA (2 km) 0 1 0 1 0 4 3

Table 5.78: Total number of each species of large gull recorded.

Lesser black- Great black- Unidentified Survey window Herring gull backed gull backed gull large gull Feb / Mar 2012 6 370 47 79 Apr / May 2012 2 105 47 5 May / Jun 2012 3 84 14 11 Jun / Aug 2012 10 27 28 131 Aug / Sep 2012 1 11 17 4 Oct / Nov 2012 12 226 56 1 Dec 2012 / Jan 2013 7 166 60 21

5.1.35.2 Distribution

During the February / March 2012 survey window, large gulls were located in many groups, scattered around the Orkney Islands mostly within 3 km off shore (Figure 5.35: A). High concentrations of large gulls were located around Westray, Rousay and Orkney Mainland. Few large gulls were located in the Pentland Firth or close to the Scottish mainland; a small group (3 – 6 birds) was located in Thurso Bay on the north-east coast of the Scottish mainland as well as a few single birds located further west along the coast.

In April / May 2012, concentrations of large gulls were recorded to the north-west of Rousay, in Burra Sound north-east of Hoy and around Pan Hope off Flotta, the majority of birds were recorded close to land (Figure 5.35: B).

In May / June 2012, a concentration of large gulls was located in the Bay of Isbister, Inganess Bay and Deer Sound off the north-west side of Orkney Mainland (Figure 5.35 : C). Smaller groups of large gulls were thinly scattered all over the survey area from Westray in the north to Loch Eriboll off the north-west of the Scottish mainland (Figure 5.35: C).

In June /August 2012, large groups of large gulls were located close to the coast around Papa Westray and Westray with smaller groups thinly scattered around the Orkney Isles and north coast of mainland Scotland (Figure 5.35: D).

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During the August / September 2012 survey, small numbers of large gulls were recorded in inshore waters around the Orkney Islands and the northern coast of the Scottish mainland, especially to the south and west of South Ronaldsay. The greatest concentration of large gulls during this survey was located off the north-west coast of Hoy (Figure 5.35: E).

In October / November 2012, high concentrations of large gulls were recorded off the northern coast of Burray, to the south of Flotta, north of Shapinsay, north-west of Eday and within Wide Firth off the Orkney Mainland (Figure 5.35: F).

During December 2012 / January 2013, large groups of large gulls were recorded north of John o’ Groats on the coast of the Scottish mainland, on the south coast of Flotta, in the Bay of Backaland on Eday and in the Bay of Pierowall off Westray (Figure 5.35:G).

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Figure 5.35: Distribution of total large gulls recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.36 Lesser black-backed gulls

5.1.36.1 Abundance estimates

Data presented in Table 5.79 refer to lesser black-backed gulls. Lesser black-backed gulls were the least abundant species of large gull recorded in the PFOW area (Table 5.78). Low numbers were recorded in all survey windows. Numbers peaked in October / November 2012 when the relative population was estimated at 453 (132 – 775) birds. Lesser black-backed gulls were recorded both within the near shore area and wider area.

Table 5.79: Raw counts, number of sightings, population estimates, confidence limits and precision for lesser black-backed gulls in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 3 2 3 10 1 9 7 Count WA (2 km) 3 0 0 0 0 3 0 Total 6 2 3 10 1 12 7 NSA (500 m) 3 2 2 5 1 8 6 Number of WA (2 km) 3 0 0 0 0 3 0 sightings Total 6 2 2 5 1 11 6 NSA (500 m) 60 39 63 244 31 194 132 Population WA (2 km) 263 0 0 0 0 259 0 Total 323 39 63 244 31 453 132 NSA (500 m) 3 2 3 49 1 65 38 LCL WA (2 km) 3 0 0 0 0 3 0 Total 20 2 3 10 1 132 24 NSA (500 m) 140 97 169 609 92 346 245 UCL WA (2 km) 613 0 0 0 0 604 0 Total 625 91 153 540 90 775 240 NSA (500 m) 0.58 0.71 0.58 0.32 >1 0.33 0.38 Precision WA (2 km) 0.58 N/A N/A N/A N/A 0.58 0 Total 0.06 0.16 0.13 0.06 0.18 0.05 0.09 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.80: Behaviour (sitting or flying) of lesser black-backed gulls in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 1 0 3 9 0 4 2 Sitting WA (2 km) 1 0 0 0 0 2 0 NSA (500 m) 2 2 0 1 1 5 5 Flying WA (2 km) 2 0 0 0 0 1 0

5.1.36.2 Distribution

In February / March 2012, three single lesser black-backed gulls were located close to the coast around the north side of the Orkney Mainland and south end of Westray (Figure 5.36: A). Another three single lesser blacked gulls were recorded offshore (> 3 km from shore) in the north-west of the survey area.

During the April / May 2012 survey window, two single lesser black-backed gulls were recorded within 1 km of land; one on off the south-west side of Hoy and the other off the south-east side of Flotta (Figure 5.36: B).

In May / June 2012, two lesser black-backed gulls were located together in the Bay of Berstane and another single bird was recorded in the Bay of Firth on the north side of Orkney Mainland (Figure 5.36: C).

In June / August 2012 survey window, the majority of lesser black-backed gulls were recorded together in a group (3 – 6 birds) in Tongue Bay with another individual close by at the entrance to Loch Eriboll off the north-west coast of Scotland (Figure 5.36: D). Two further individual lesser black-backed gulls were located on either side of South Ronaldsay and another in Taracliff Bay on the south-east side of Orkney Mainland (Figure 5.36: D).

During the August / September 2012 survey, one lesser black-backed gull was recorded along the northern coast of the Scottish mainland, off Scarfskerry Point (Figure 5.36: E).

Single lesser black-backed gulls were widely scattered across the PFOW survey area during October / November 2012 and two individuals were recorded in close proximity off the southern coast of Orkney Mainland (Figure 5.36: F).

During the December 2012 / January 2013 survey window, a small group of lesser black- backed gulls were recorded close to shore in the Bay of Backaland in the South of Eday, with individuals observed on the north-east tip of Wyre, to the west of Yesnaby on the coast of the Orkney Mainland and off the north coast of Graemsay (Figure 5.36: G).

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Figure 5.36: Distribution of lesser black-backed gulls recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.37 Herring gulls

5.1.37.1 Abundance estimates

Data presented in Table 5.81 refer to herring gulls. Generally herring gulls were the most abundant species of large gulls recorded in the PFOW area (Table 5.78) and small - moderate numbers of herring gulls were recorded in all survey windows. Numbers peaked in February / March 2012 when the relative population was estimated at 7,628 (3,828 – 11,427) birds. Herring gulls were recorded both within the near shore area and wider area, although the majority herring gulls were recorded within the near shore area.

Table 5.81: Raw counts, number of sightings, population estimates, confidence limits and precision for herring gulls in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 367 105 82 26 10 219 164 Count WA (2 km) 3 0 2 1 1 7 2 Total 370 105 84 27 11 226 166 NSA (500 m) 82 49 36 21 8 78 57 Number of WA (2 km) 3 0 2 1 1 3 2 sightings Total 85 49 38 22 9 81 59 NSA (500 m) 7,365 2,037 1,729 634 307 4,730 3,097 Population WA (2 km) 263 0 188 88 113 604 209 Total 7,628 2,037 1,918 721 420 5,334 3,306 NSA (500 m) 4,134 1,242 780 341 92 2,570 1,511 LCL WA (2 km) 3 0 2 1 1 7 2 Total 3,828 1,170 706 387 97 2,483 1,572 NSA (500 m) 11,479 3,007 3,058 926 553 8,100 5,079 UCL WA (2 km) 613 0 564 263 339 1,467 523 Total 11,427 2,904 3,129 1,055 744 8,186 5,039 NSA (500 m) 0.05 0.10 0.11 0.2 0.32 0.07 0.08 Precision WA (2 km) 0.58 N/A 0.71 >1 >1 0.38 0.71 Total 0.01 0.02 0.02 0.04 0.05 0.01 0.02 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.82: Behaviour (sitting or flying) herring gulls in the PFOW area for each survey.

Survey Window Feb / Apr / May / Jun / Aug Oct / Dec 2012 Mar May Jun Aug /Sep Nov / Jan 2013 2012 2012 2012 2012 2012 2012 NSA (500 m) 289 21 65 9 6 172 68 Sitting WA (2 km) 2 0 2 1 1 5 1 NSA (500 m) 78 84 17 17 4 47 96 Flying WA (2 km) 1 0 0 0 0 2 1

5.1.37.2 Distribution

In February / March 2012, herring gulls were located close to the coast around the Orkney Islands, there were few birds recorded in the Pentland Firth or along the north coast of the Scottish mainland (Figure 5.37: A). Herring gulls were concentrated around the coasts of Papa Westray, Westray, north Rousay, north Orkney Mainland and west of Burray (Figure 5.37: A).

During the April / May 2012 survey window, herring gulls were generally scattered throughout the Orkney Isles with large concentrations in Hoy Sound and Burra Sound off the north-west coast of Hoy, Pan Hope off Flotta, Bays of Isbister and Kirkwall off the north coast Orkney Mainland and Fersness Bay off Eday (Figure 5.37: B).

In May / June 2012, a few groups of herring gulls were scattered around the Orkney Islands; the largest group (7 – 10 birds) was located in the Bay of Isbister off Mainland Orkney (Figure 5.37: C).

In June / August 2012, a few herring gulls were recorded, many as single birds around the coasts of Rousay, Eday and Orkney Mainland (Figure 5.37: D). The largest group (7 – 10 birds) of herring gulls recorded in July was located in Hoston Bay on the south-west side of South Ronaldsay.

During the August / September 2012 survey, a group of 3 – 6 herring gulls was recorded off the north-west coast of Hoy and single individuals were widely dispersed throughout the inshore waters around the Orkney Islands and along the northern coast of the Scottish mainland (Figure 5.37: E).

In October / November 2012, higher numbers of herring gulls were recorded with the largest concentrations of individuals recorded to the north of Burray, south of Flotta, north of Shapinsay, north-west of Eday and around the south-eastern coast of Orkney Mainland as well as in Wide Firth off Orkney Mainland (Figure 5.37: F).

During December 2012 / January 2013, large groups of herring gulls were recorded north of John o’ Groats along the coast of the Scottish mainland, on the south coast of Flotta, in the Bay of Backaland on Eday and in the Bay of Pierowall off Westray (Figure 5.37:G). Smaller groups and individual herring gulls were loosely distributed throughout the PFOW survey area, from the far north-west of the site close to the survey area boundary to north of Durness on the Scottish Mainland in the far south-west of the survey area (Figure 5.37:G). 151

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Figure 5.37: Distribution of herring gulls recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.38 Great black-backed gulls

5.1.38.1 Abundance estimates

Data presented in Table 5.83 refer to great black-backed gulls. Low to moderate numbers of great black-backed gulls were recorded in all survey windows. Numbers peaked in October / November 2012 when the relative population was estimated at 1,468 (981 – 1,955). Great black-backed gulls were recorded within the near shore area and wider area, although the majority were recorded within the near shore area in all survey windows.

Table 5.83: Raw counts, number of sightings, population estimates, confidence limits and precision for great black-backed gulls in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 43 43 13 27 16 52 59 Count WA (2 km) 4 4 1 1 1 4 1 Total 47 47 14 28 17 56 60 NSA (500 m) 35 20 11 21 16 44 39 Number of WA (2 km) 3 3 1 1 1 4 1 sightings Total 38 23 12 22 17 48 40 NSA (500 m) 863 834 274 658 492 1,123 1,114 Population WA (2 km) 350 318 95 88 113 345 105 Total 1,213 1,152 368 746 605 1,468 1,219 NSA (500 m) 542 330 105 390 277 778 661 LCL WA (2 km) 4 4 1 1 1 86 1 Total 689 441 114 390 282 981 652 NSA (500 m) 1,184 1,494 464 1,048 738 1,512 1,737 UCL WA (2 km) 876 715 286 263 339 690 314 Total 1,737 1,863 662 1,102 928 1,955 1,785 NSA (500 m) 0.15 0.15 0.28 0.19 0.25 0.14 0.13 Precision WA (2 km) 0.50 0.50 >1 >1 >1 0.5 >1 Total 0.03 0.03 0.05 0.04 0.04 0.03 0.03 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.84: Behaviour (sitting or flying) of great black-backed gulls in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 21 24 7 14 4 42 30 Sitting WA (2 km) 4 3 1 1 1 3 0 NSA (500 m) 22 19 6 13 12 10 29 Flying WA (2 km) 0 1 0 0 0 1 1

5.1.38.2 Distribution

In February / March 2012, great black-backed gulls were generally located close to shore in small groups around the Orkney Islands, few great black-backed gulls were recorded in the Pentland Firth or off the north coast of Scotland (Figure 5.38: A). The main congregation of these small groups were located around the mid - north Orkney Islands, including the north side of the Orkney Mainland, Rousay and Westray.

In April / May 2012 , the majority of great black-backed gulls were clumped together at the north-west tip of Rousay with another group located in Pan Hope off Flotta. Further single great black-backed gulls were recorded scattered throughout the Orkney Islands and off the Scottish mainland coast (Figure 5.38: B).

In May / June 2012, few great black-backed gulls were recorded; the main group (3 – 6 birds) was located in Deer Sound on the north-east coast of the Orkney Mainland with a few scattered single groups scattered around other Orkney Islands (Figure 5.38: C).

In June / August 2012, few great black-backed gulls were again recorded; the largest groups (3 – 6 birds) was located close to Clivie Bay off the south-east side of the Orkney Mainland and on the south-west point of Shapinsay (Figure 5.38: D).

In August / September 2012, low numbers of single great black-backed gulls were recorded throughout the inshore waters of the PFOW survey area, particularly around the southern Orkney Islands. A single great black-backed gull was also recorded further offshore in the western half of the PFOW area (Figure 5.38: E).

In October / November 2012 higher numbers of great black-backed gulls were recorded in inshore waters with concentrations located to the north-west of Eday, south-east of Rousay and south of Shapinsay. Single great black-backed gulls were also recorded further offshore from Duncansby Head and the northern coast of the Scottish mainland, in addition to the far north-west of the PFOW survey area, close to the outer survey boundary (Figure 5.38: F).

During the December 2012 / January 2013 survey window, the majority of great black- backed gulls were recorded close to the Bay of Backaland on the east coast of Eday, with smaller groups (3 – 6 birds) observed on the south coast of Flotta and south of Deerness off the Orkney Mainland (Figure 5.38:G).

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Figure 5.38: Distribution of great black-backed gulls recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.39 Total terns

5.1.39.1 Abundance estimates

Data presented in Table 5.85 refer to total terns (including Arctic terns, ‘commic’ common or Arctic terns and terns not identified to species level). Moderate numbers of terns were recorded during the May / June 2012 and June / August 2012 survey windows. Numbers peaked in May / June 2012 when the relative population was estimated at 5,961 (2,767 – 9,156) birds. Terns were recorded within the near shore area and wider area, although the majority were recorded within the near shore area in all survey windows. The numbers of terns identified to species level is presented in Table 5.87. Relative population estimates for terns that could be identified to species are provided in subsequent sections.

Table 5.85: Raw counts, number of sightings, population estimates, confidence limits and precision for total terns in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 189 79 13 0 0 Count WA (2 km) 0 0 21 1 3 0 0 Total 0 0 210 80 16 0 0 NSA (500 m) 0 0 50 32 11 0 0 Number of WA (2 km) 0 0 9 1 3 0 0 sightings Total 0 0 59 33 14 0 0 NSA (500 m) 0 0 3,986 1,926 400 0 0 Population WA (2 km) 0 0 1,975 88 339 0 0 Total 0 0 5,961 2,013 738 0 0 NSA (500 m) 0 0 1,793 902 184 0 0 LCL WA (2 km) 0 0 564 1 3 0 0 Total 0 0 2,767 825 286 0 0 NSA (500 m) 0 0 7,382 3,364 676 0 0 UCL WA (2 km) 0 0 4,138 263 791 0 0 Total 0 0 9,156 3,202 1,191 0 0 NSA (500 m) N/A N/A 0.07 0.11 0.28 N/A N/A Precision WA (2 km) N/A N/A 0.22 >1 0.58 N/A N/A Total N/A N/A 0.01 0.02 0.04 N/A N/A Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.86: Behaviour (sitting or flying) of total terns in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 1 10 0 0 0 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 188 69 13 0 0 Flying WA (2 km) 0 0 21 1 3 0 0

Table 5.87: Total number of each species of tern recorded.

Survey window Arctic tern ‘Commic’ tern Unidentified tern Feb / Mar 2012 0 0 0 Apr / May 2012 0 0 0 May / Jun 2012 0 0 210 Jun / Aug 2012 36 0 18 Aug / Sep 2012 0 16 0 Oct / Nov 2012 0 0 0 Dec 2012 / Jan 2013 0 0 0 ‘Commic’ tern: Common or Arctic tern

5.1.39.2 Distribution

In May / June 2012 survey window, terns were located throughout the Orkney Islands archipelagos with single individuals recorded further offshore towards the west of the wider PFOW survey area (Figure 5.39: A). High concentrations of individuals were located off the southern tip of South Ronaldsay in the Pentland Firth, off the western coast of Westray, the south of Hoy and the northern tip of Graemsay (Figure 5.39: A).

In June / August 2012 survey window, terns were largely located in the north of the survey areas, with concentrations off Spo Ness on Westray and within Backaskaill Bay on Sanday. Smaller numbers of terns were recorded around the coasts of Rousay, in the Gairsay Sound, off the southern coast of Orkney Mainland and off the Island of Stroma (Figure 5.39: B).

During the August / September 2012 survey, terns were recorded off the north-west coast of Hoy, around the coasts of Eday, to the south of Westray, off Duncansby Head on the Scottish mainland and in the far north of the PFOW survey area, close to the outer boundary (Figure 5.39: C).

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Figure 5.39: Distribution of total terns recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: May / June 2012 B: June / August 2012

C: August / September 2012

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5.1.40 Arctic terns

5.1.40.1 Abundance estimates

Data presented in Table 5.88 refer to Arctic terns. Small numbers of Arctic terns were recorded in June / August 2012 within the near shore area at an estimated 878 (482 – 1,273) birds.

Table 5.88: Raw counts, number of sightings, population estimates, confidence limits and precision for Arctic terns in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 36 0 0 0 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 36 0 0 0 NSA (500 m) 0 0 0 23 0 0 0 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 0 0 0 23 0 0 0 NSA (500 m) 0 0 0 878 0 0 0 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 878 0 0 0 NSA (500 m 0 0 0 488 0 0 0 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 482 0 0 0 NSA (500 m) 0 0 0 1,316 0 0 0 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 1,273 0 0 0 NSA (500 m) N/A N/A N/A 0.17 N/A N/A N/A Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total N/A N/A N/A 0.03 N/A N/A N/A Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.89: Behaviour (sitting or flying) of Arctic terns in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 0 0 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 36 0 0 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.40.2 Distribution

In June / August 2012, Arctic terns were recorded in inshore waters around the coasts of Westray, to the north of Rousay around Saviskaill Bay and Saviskaill Head, within the Eynhallow and Gairsay Sounds, within Wide Firth and off the southern coast of Orkney Mainland at Howequoy Head (Figure 5.40: A).

Figure 5.40: Distribution of Arctic terns recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: June / August 2012

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5.1.41 Commic terns

5.1.41.1 Abundance estimates

Data presented in Table 5.90 refer to ‘commic’ common or Arctic terns. Low numbers of commic terns were recorded during the August / September 2012 survey when the relative population was estimated at 738 (286 – 1,191). Commic terns were recorded within the near shore area and wider area, although the majority were recorded within the near shore area.

Table 5.90: Raw counts, number of sightings, population estimates, confidence limits and precision for ‘Commic’ terns in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 13 0 0 Count WA (2 km) 0 0 0 0 3 0 0 Total 0 0 0 0 16 0 0 NSA (500 m) 0 0 0 0 11 0 0 Number of WA (2 km) 0 0 0 0 3 0 0 sightings Total 0 0 0 0 14 0 0 NSA (500 m) 0 0 0 0 400 0 0 Population WA (2 km) 0 0 0 0 339 0 0 Total 0 0 0 0 738 0 0 NSA (500 m) 0 0 0 0 184 0 0 LCL WA (2 km) 0 0 0 0 3 0 0 Total 0 0 0 0 286 0 0 NSA (500 m) 0 0 0 0 676 0 0 UCL WA (2 km) 0 0 0 0 791 0 0 Total 0 0 0 0 1,191 0 0 NSA (500 m) N/A N/A N/A N/A 0.28 N/A N/A Precision WA (2 km) N/A N/A N/A N/A 0.58 N/A N/A Total N/A N/A N/A N/A 0.04 N/A N/A Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.91: Behaviour (sitting or flying) of commic terns in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 0 0 Sitting WA (2 km) 0 0 0 0 0 0 0 NSA (500 m) 0 0 0 0 13 0 0 Flying WA (2 km) 0 0 0 0 3 0 0

5.1.41.2 Distribution

During the August / September 2012 survey, commic terns were recorded off the north-west coast of Hoy, around the coasts of Eday, to the south of Westray, off Duncansby Head on the Scottish mainland and in the far north of the PFOW survey area, close to the outer boundary (Figure 5.41: A).

Figure 5.41: Distribution of commic terns recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: August / September 2012

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5.1.42 Total auks

5.1.42.1 Abundance estimates

Data presented in Table 5.92 refer to total auks (including common guillemots, razorbills, black guillemots, puffins and auks not identified to species level). Moderate numbers of auks were recorded in all survey windows. Numbers peaked in May / June 2012 when the relative population was estimated at 39,223 (23,440 – 55,007) birds. Auks were recorded within the near shore area and wider area. The numbers of auks identified to species level is presented in Table 5.94. Relative population estimates for auks that could be identified to species are provided in subsequent sections.

Table 5.92: Raw counts, number of sightings, population estimates, confidence limits and precision for total auks in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 257 172 1,231 307 71 263 213 Count WA (2 km) 90 121 141 41 34 63 25 Total 347 293 1,372 348 105 326 238 NSA (500 m) 44 27 167 103 34 151 97 Number of WA (2 km) 31 38 39 9 21 43 15 sightings Total 75 65 206 112 55 194 112 NSA (500 m) 5,157 3,337 25,963 7,484 2,182 5,681 4,022 Population WA (2 km) 7,880 9,609 13,260 3,589 3,841 5,437 2,614 Total 13,037 12,946 39,223 11,073 6,023 11,118 6,636 NSA (500 m) 2,408 1,630 15,755 5,314 1,322 4,493 2,851 LCL WA (2 km) 4,028 6,036 6,771 525 2,033 3,625 1,255 Total 7,137 8,782 23,440 5,903 3,869 8,750 4,713 NSA (500 m) 9,673 5,471 42,710 10,116 3,258 7,020 5,438 UCL WA (2 km) 12,608 13,501 21,536 9,367 5,874 7,508 4,182 Total 18,938 17,111 55,007 16,243 8,178 13,486 8,559 NSA (500 m) 0.06 0.08 0.03 0.06 0.12 0.06 0.07 Precision WA (2 km) 0.11 0.09 0.08 0.16 0.17 0.13 0.2 Total 0.01 0.01 <0.01 0.01 0.01 0.01 0.01 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.93: Behaviour (sitting or flying) of total auks in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar20 May Jun Aug /Sep Nov Jan 12 2012 2012 2012 2012 2012 2013 NSA (500 m) 221 164 956 265 70 260 205 Sitting WA (2 km) 90 121 98 40 34 63 24 NSA (500 m) 36 8 275 42 1 3 8 Flying WA (2 km) 0 0 43 1 0 0 1

Table 5.94: Total number of each species of auk recorded.

Common Survey Common Black Unidentified guillemots or Razorbills Puffins window guillemots guillemots auk razorbills Feb / Mar 342 32 15 1 0 4 2012 Apr / May 291 8 1 0 0 2 2012 May / Jun 1366 347 25 4 2 0 2012 Jun / Aug 287 149 40 41 1 19 2012 Aug / Sep 80 32 10 22 3 0 2012 Oct / Nov 184 0 0 123 19 0 2012 Dec 2012 214 12 0 24 0 0 / Jan 2013

5.1.42.2 Distribution

In February / March 2012, auks were distributed throughout much of the PFOW survey area, with higher concentrations of auks recorded off the west coast of Orkney Mainland at Costa Head and Marwick Head, off the Island of Stroma in the Pentland Firth and further offshore in the north-west of the wider PFOW survey area (Figure 5.42: A).

During the April / May 2012 survey window, a similar distribution to the previous survey window was recorded. Auks were distributed throughout much of the PFOW survey area, with higher concentrations of auks recorded beyond the 3 km land boundary to the west of the Orkney Mainland and to the north-west of Westray. Some large clusters were also recorded in the Pentland Firth to the west of the island of Stroma (Figure 5.42: B).

In May / June 2012, auks were associated more closely with coastal areas (Figure 5.42: C). Concentrations of auks were located along the northern coast of the Scottish mainland, 166

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In June / August 2012, auk numbers had decreased compared to the previous survey, with most auks located close to the northern coast of mainland Scotland and a high concentration was recorded around Duncansby Head and Port Vasgo (Figure 5.42: D). Auks were also recorded within Scapa Flow, along the western coasts or Hoy and Orkney Mainland, within Wide Firth and around the coasts of Westray and Papa Westray (Figure 5.42: D).

During the August / September 2012 survey, auks were widely dispersed across the PFOW survey area with higher concentrations of individuals recorded close to and offshore from Strathy Point on the Scottish mainland (Figure 5.42: E). Groups of 3 – 6 auks were also recorded within Scapa Flow, off Mull Head on Papa Westray, within Wide Firth off Orkney Mainland and in the south-eastern corner of the PFOW survey area near to Duncansby Head (Figure 5.42: E).

Higher numbers of auks were recorded in inshore waters around the Orkney Islands during the October / November 2012 survey with aggregations located north of Rousay, north-west of Eday, west of Sanday and south-east of South Ronaldsay (Figure 5.42: F). Groups of up to six auks were also recorded further offshore in the west of the PFOW survey area (Figure 5.42: F).

During the December 2012 / January 2013 survey window, auk numbers had decreased compared to the previous survey window, with high concentrations of auks located off Marwick Head on the west coast of the Orkney Mainland and off Sacquoy Head off Rousay (Figure 5.42:G).

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Figure 5.42: Distribution of total auks recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.43 Total common guillemots and razorbills

5.1.43.1 Abundance estimates

Data presented in Table 5.95 refer to total common guillemots and razorbills. Common guillemots and razorbills together formed the most abundant group of auks recorded in the PFOW area and moderate to large numbers were recorded in all survey windows. Numbers peaked in May / June 2012 when the relative population was estimated at 39,097 (23,314 – 54,880) birds (99.3 % of total auks). Common guillemots and razorbills were recorded within the near shore area and wider area.

Table 5.95: Raw counts, number of sightings, population estimates, confidence limits and precision for total common guillemots and razorbills in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 252 170 1,225 272 52 144 192 Count WA (2 km) 90 121 141 15 28 40 22 Total 342 291 1,366 287 80 184 214 NSA (500 m) 42 26 166 92 27 80 79 Number of WA (2 km) 31 38 39 8 19 32 13 sightings Total 73 64 205 100 46 112 92 NSA (500 m) 5,057 3,298 25,837 6,630 1,598 3,110 3,625 Population WA (2 km) 7,880 9,609 13,260 1,313 3,163 3,452 2,300 Total 12,937 12,907 39,097 7,944 4,761 6,563 5,926 NSA (500 m) 2,268 1,668 15,439 4,583 922 2,182 2,398 LCL WA (2 km) 3,940 6,115 6,771 350 1,694 2,158 1,046 Total 7,038 8,748 23,314 10,515 3,003 4,951 4,064 NSA (500 m) 9,312 5,335 40,938 9,239 2,521 4,169 5,041 UCL WA (2 km) 13,308 13,739 21,724 2,451 4,970 4,833 3,869 Total 18,836 17,066 54,880 5,372 6,520 8,174 7,787 NSA (500 m) 0.06 0.08 0.03 0.06 0.14 0.08 0.07 Precision WA (2 km) 0.11 0.09 0.08 0.26 0.19 0.16 0.21 Total 0.01 0.01 <0.01 0.01 0.01 0.01 0.01 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.96: Behaviour (sitting or flying) of total common guillemots and razorbills in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 219 163 950 235 51 0 184 Sitting WA (2 km) 90 121 98 14 28 0 21 NSA (500 m) 33 7 275 37 1 0 8 Flying WA (2 km) 0 0 43 1 0 0 1

5.1.43.2 Distribution

In February / March 2012, common guillemots and razorbills were distributed throughout much of the PFOW survey area, with higher concentrations of common guillemots and razorbills recorded off the west coast of Orkney Mainland at Costa Head and Marwick Head, off the Island of Stroma in the Pentland Firth and further offshore in the north-west of the wider PFOW survey area (Figure 5.43: A).

During the April / May 2012 survey window, clusters of up to ten common guillemots and razorbills were recorded offshore throughout the west, south-west and north-west of the wider PFOW survey area (Figure 5.43: D). Larger aggregations of up to 30 individuals were recorded off Marwick Head and Costa Head on the west coast of Orkney Mainland, off the north-western tip of Shapinsay, within Deer Sound on the eastern side of Orkney Mainland and along the northern coast of mainland Scotland (Figure 5.43: D).

In May / June 2012, common guillemots and razorbills were associated more closely with coastal areas (Figure 5.43: C). Concentrations of common guillemots and razorbills were located along the northern coast of the Scottish mainland, particularly around Dunnet Head, Port Vasgo and Duncansby Head, with further aggregations recorded around the southern and western coasts of Hoy, the south of South Ronaldsay, off Marwick Head on Orkney Mainland, to the north of Rousay, within the Stronsay Firth and off Noup Head on Westray (Figure 5.43: C).

In June / August 2012 survey window, common guillemot and razorbill numbers had decreased compared with the previous survey, with most common guillemots and razorbills located close to the northern coast of mainland Scotland, with a high concentration around Duncansby Head and Port Vasgo (Figure 5.43: D). Common guillemots and razorbills were also recorded within Scapa Flow, along the western coasts or Hoy and Orkney Mainland, within Wide Firth and around the coasts of Westray and Papa Westray (Figure 5.43: D).

During the August / September 2012 survey, common guillemots and razorbills were widely dispersed across the PFOW survey area with higher concentrations of individuals recorded close to and offshore from Strathy Point on the Scottish mainland (Figure 5.43: E). Groups of 3 – 6 auks were also recorded within Scapa Flow, off Mull Head on Papa Westray, within

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Wide Firth off Orkney Mainland and in the south-eastern corner of the PFOW survey area near to Duncansby Head (Figure 5.43: E).

Higher numbers of common guillemots and razorbills were recorded in inshore waters around the Orkney Islands during the October / November 2012 survey with aggregations located north of Rousay, north-west of Eday, west of Sanday and south-east of South Ronaldsay (Figure 5.43: F). Groups of up to six common guillemots and razorbills were also recorded further offshore in the west of the PFOW survey area (Figure 5.43: F).

During the December 2012 / January 2013 survey window, common guillemot and razorbill numbers had decreased compared to the previous survey window, with high concentrations of common guillemots and razorbills observed off Marwick Head on the west coast of the Orkney Mainland and off Sacquoy Head on Rousay (Figure 5.43:G).

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Figure 5.43: Distribution of total common guillemots & razorbills recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.1.44 Common guillemots

5.1.44.1 Abundance estimates

Data presented in Table 5.97 refer to common guillemots. Common guillemots were the most abundant of the auk family to be identified to species in the PFOW area (Table 5.94). Low to moderate numbers of common guillemots were recorded in all survey windows except October / November 2012. Numbers peaked in May / June 2012 when the relative population was estimated at 12,352 (7,801 – 16,903) birds. Common guillemots were recorded within the near shore area and wider area; the majority were recorded within the near shore area.

Table 5.97: Raw counts, number of sightings, population estimates, confidence limits and precision for common guillemots in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 30 8 278 140 27 0 10 Count WA (2 km) 2 0 69 9 5 0 2 Total 32 8 347 149 32 0 12 NSA (500 m) 6 2 63 55 11 0 9 Number of WA (2 km) 2 0 26 5 5 0 1 sightings Total 8 2 89 60 16 0 10 NSA (500 m) 602 155 5,863 3,413 830 0 189 Population WA (2 km) 175 0 6,489 788 565 0 209 Total 777 155 12,352 4,201 1,395 0 398 NSA (500 m) 60 8 3,311 2,048 277 0 76 LCL WA (2 km) 2 0 3,386 88 113 0 2 Total 57 8 7,801 2,530 596 0 12 NSA (500 m) 1,405 388 9,154 5,192 1,537 0 321 UCL WA (2 km) 438 0 10,439 1,576 1,130 0 627 Total 1,498 365 16,903 5,871 2,193 0 824 NSA (500 m) 0.18 0.35 0.06 0.08 0.19 N/A 0.32 Precision WA (2 km) 0.71 N/A 0.12 0.33 0.45 N/A 0.71 Total 0.04 0.08 0.01 0.02 0.03 N/A 0.05 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.98: Behaviour (sitting or flying) of common guillemots in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 10 4 143 105 26 0 10 Sitting WA (2 km) 2 0 38 8 5 0 2 NSA (500 m) 20 4 135 35 1 0 0 Flying WA (2 km) 0 0 31 1 0 0 0

5.1.44.2 Distribution

In February / March 2012, common guillemots were recorded in clusters of up to six individuals off Duncansby Head on the north-eastern coast of the Scottish mainland (Figure 5.44: A). A large cluster of up to ten individuals was recorded off Red Head to the north of Eday and small numbers of one or two individuals were located in the Pentland Firth, off the western coast of Orkney Mainland and off the eastern coast of Shapinsay (Figure 5.44: A).

In April / May 2012, clusters of up to six common guillemots were recorded off Dunnet Head on the north-east coast of the Scottish mainland and also off the western coast of Westray (Figure 5.44: B).

In May / June 2012, higher numbers of common guillemots were recorded, with the highest concentrations located within the Pentland Firth and along the northern coast of the Scottish mainland (Figure 5.44: C). Groups of up to 30 common guillemots were also located off the west of Westray, off Sacquoy Head on Rousay and off Mull Head to the north of Papa Westray (Figure 5.44: C).

In June / August 2012, common guillemot numbers had reduced, although the highest concentrations were still recorded along the northern coast of the Scottish mainland (Figure 5.44: D). Smaller groups of one or two common guillemots were scattered throughout the Orkney archipelagos, particularly within Scapa Flow, the Gairsay Sound and off the western coast of Westray (Figure 5.44: D). Common guillemots were also located further offshore within the south-western part of the wider PFOW survey area (Figure 5.44: D).

During the September / October 2012 survey, groups of up to six common guillemots were recorded to the east of Strathy Point on the Scottish mainland and also within Scapa Flow (Figure 5.44: E). Single guillemots were also recorded and were widely scattered throughout the inshore waters surrounding the Orkney Islands and along the northern coast of mainland Scotland (Figure 5.44: E).

Low numbers of common guillemots were recorded during the December 2012 / January 2013 survey window, with pairs of common guillemots recorded to the east of Papa Westray close to the Pentland Firth Survey Area boundary and between Rousay and Orkney Island (Figure 5.44:E). Single sitting common guillemots were observed in the Bay of Tuquoy and north of Cleat on Westray, in Veantrow Bay off Shapinsay, to the east of Gairsay and north of Hunda (Figure 5.44: F). 176

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Figure 5.44: Distribution of common guillemots recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: December 2012 / January 2013

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5.1.45 Razorbills

5.1.45.1 Abundance estimates

Data presented in Table 5.99 refer to razorbills. Razorbills were the second most abundant of the auk family to be identified to species in the PFOW area (after common guillemots; Table 5.94). Low numbers of razorbills were recorded in all survey windows except October / November 2012 and December 2012 / January 2013. Numbers peaked in June / August 2012 when the relative population was estimated at 1,038 (40 – 2,086) birds. The majority of razorbills were recorded within the near shore area.

Table 5.99: Raw counts, number of sightings, population estimates, confidence limits and precision for razorbills in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 11 1 25 39 4 0 0 Count WA (2 km) 4 0 0 1 6 0 0 Total 15 1 25 40 10 0 0 NSA (500 m) 4 1 8 11 4 0 0 Number of WA (2 km) 3 0 0 1 5 0 0 sightings Total 7 1 8 12 9 0 0 NSA (500 m) 221 19 527 951 123 0 0 Population WA (2 km) 350 0 0 88 678 0 0 Total 571 19 527 1,038 801 0 0 NSA (500 m) 20 1 105 195 4 0 0 LCL WA (2 km) 4 0 0 1 113 0 0 Total 90 1 84 40 167 0 0 NSA (500 m) 522 58 1,012 2,169 246 0 0 UCL WA (2 km) 788 0 0 263 1,356 0 0 Total 1,052 56 971 2,086 1,434 0 0 NSA (500 m) 0.30 >1 0.20 0.16 0.5 N/A N/A Precision WA (2 km) 0.50 N/A N/A >1 0.41 N/A N/A Total 0.04 0.23 0.04 0.03 0.04 N/A N/A Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.100: Behaviour (sitting or flying) of razorbills in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 6 0 19 39 4 0 0 Sitting WA (2 km) 4 0 0 1 6 0 0 NSA (500 m) 5 1 6 0 1 0 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.45.2 Distribution

In February / March 2012, four razorbills were identified to the north-west beyond the 3 km land boundary off Mainland Orkney (Figure 5.45: A). In the same survey window within the 3 km boundary, several groups of razorbills were clustered around Marwick Head on the west side of Orkney Mainland and one individual was recorded off Red Head on Eday (Figure 5.45: A).

During the April / May 2012 survey window, one razorbill was recorded close to Billia Croo off the south-west Orkney Mainland (Figure 5.45: B).

In May / June 2012, the majority of razorbills were recorded in the Pentland Firth with several groups (3 – 6 birds in each) located around Faraid Head on the north coast of Scottish mainland (Figure 5.45: C).

In June / August 2012 survey window, razorbills were clustered largely around the north- eastern tip of the Scottish mainland at Duncansby Head (Figure 5.45: D), with further individuals recorded along this coastline at Torrisdale Bay. Small numbers of one or two razorbills were recorded within the Orkney archipelagos within Scapa Flow, Gairsay Sound and off the western coast of Westray (Figure 5.45: D).

Low numbers of razorbills were recorded during September / October 2012 with individuals widely scattered throughout the PFOW survey area (Figure 5.45: E). A group of two razorbills were recorded off the north-western tip of Westray (Figure 5.45: E).

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Figure 5.45: Distribution of razorbills recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August /September 2012

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5.1.46 Black guillemots

5.1.46.1 Abundance estimates

Data presented in Table 5.101 refer to black guillemots. Low numbers of black guillemots were recorded in all survey windows except April / May 2012. Numbers were highest in October / November 2012 when the relative population was estimated at 3,627 (2,040 – 5,215). The majority of black guillemots were recorded within the near shore area; with lower numbers recorded in the wider area.

Table 5.101: Raw counts, number of sightings, population estimates, confidence limits and precision for black guillemots in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 1 0 4 31 19 108 21 Count WA (2 km) 0 0 0 10 3 15 3 Total 1 0 4 41 22 123 24 NSA (500 m) 1 0 3 13 7 68 18 Number of WA (2 km) 0 0 0 1 1 7 2 sightings Total 1 0 3 14 8 75 20 NSA (500 m) 20 0 84 756 584 2,333 397 Population WA (2 km) 0 0 0 875 339 1,295 314 Total 20 0 84 1,631 923 3,627 710 NSA (500 m) 1 0 4 293 92 1,663 227 LCL WA (2 km) 0 0 0 10 3 259 3 Total 1 0 4 41 61 2,040 218 NSA (500 m) 60 0 211 1,292 1,230 3,110 585 UCL WA (2 km) 0 0 0 2,626 1,017 3,021 836 Total 58 0 183 3,404 1,784 5,215 1,203 NSA (500 m) >1 N/A 0.50 0.18 0.23 0.1 0.22 Precision WA (2 km) N/A N/A N/A 0.32 0.58 0.26 0.58 Total 0.22 N/A 0.11 0.02 0.03 0.02 0.04 Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.102: Behaviour (sitting or flying) of black guillemots in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 2 26 19 107 21 Sitting WA (2 km) 0 0 0 10 3 15 3 NSA (500 m) 1 0 0 5 0 1 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.46.2 Distribution

In February / March 2012, a black guillemot was recorded within 2 km of the north-west coast of Rousay (Figure 5.46: A).

In May / June 2012, two black guillemots were recorded within 3 km of Midland Ness on the south side of the Orkney Mainland, while a further two individuals were recorded in Eynhallow Sound between Orkney Mainland and Rousay (Figure 5.46: B).

In June / August 2012, 31 black guillemots were recorded, with the highest concentrations located in the Pentland Firth and off Duncansby Head on the north-eastern tip of the Scottish mainland (Figure 5.46: C).

During the August / September 2012 survey, black guillemots were recorded to the north-east of Eday and off Broad Taing on Orkney Mainland (Figure 5.46: D). Further black guillemots were recorded along the northern coastline of the Scottish mainland within Dunnet Bay, Sandside Bay and Melvich Bay (Figure 5.46: D).

In October / November 2012, high numbers of black guillemots were recorded in inshore waters around the Orkney Islands with the highest concentrations recorded off Broad Taing and in Deer Sound off Orkney Mainland, around the coastline of Burray, off the north-east of Eday and off the south-east coast of South Ronaldsay (Figure 5.46: E).

During December 2012 / January 2013, pairs of black guillemots were recorded off Noup Head on Westray, north of Rendall on the Orkney Mainland, north of Baligill on the Scottish mainland and to the far west of Westray on the boundary of the Pentland Firth Survey Area (Figure 5.46: F). Individual black guillemots were also recorded to the west of Papa Westray, off the north and west coast of Shapinsay, along the north and south coast of the Orkney Mainland, to the east of Hoy and South Ronaldsay (Figure 5.46: F).

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Figure 5.46: Distribution of black guillemots recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: February / March 2012 B: May / June 2012

C: June / August 2012 D: August / September 2012

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E: October / November 2012 F: December 2012 / January 2013

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5.1.47 Puffins

5.1.47.1 Abundance estimates

Data presented in Table 5.103 refer to puffins. Puffins were the least abundant of the auk family to be identified to species in the PFOW area (Table 5.94) and generally very low numbers were recorded. The peak number was recorded during the October / November 2012 survey window when the relative population was estimated at 928 (331 – 1,525) birds. The majority of puffins were recorded within the near shore area.

Table 5.103: Raw counts, number of sightings, population estimates, confidence limits and precision for puffins in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 2 1 0 11 0 Count WA (2 km) 0 0 0 0 3 8 0 Total 0 0 2 1 3 19 0 NSA (500 m) 0 0 1 1 0 11 0 Number of WA (2 km) 0 0 0 0 3 6 0 sightings Total 0 0 1 1 3 17 0 NSA (500 m) 0 0 42 24 0 238 0 Population WA (2 km) 0 0 0 0 339 690 0 Total 0 0 42 24 339 928 0 NSA (500 m) 0 0 2 1 0 108 0 LCL WA (2 km) 0 0 0 0 3 173 0 Total 0 0 2 1 3 331 0 NSA (500 m) 0 0 127 73 0 389 0 UCL WA (2 km) 0 0 0 0 791 1,295 0 Total 0 0 123 71 720 1,525 0 NSA (500 m) N/A N/A 0.71 >1 N/A 0.3 N/A Precision WA (2 km) N/A N/A N/A N/A 0.58 0.35 N/A Total N/A N/A 0.15 0.2 0.05 0.03 N/A Number of sightings: Number of images that contained birds, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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Table 5.104: Behaviour (sitting or flying) of puffins in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar20 May Jun Aug /Sep Nov Jan 12 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 2 1 0 11 0 Sitting WA (2 km) 0 0 0 0 3 8 0 NSA (500 m) 0 0 0 0 0 0 0 Flying WA (2 km) 0 0 0 0 0 0 0

5.1.47.2 Distribution

In May / June 2012, two puffins were identified close to Faraid Head on the north coast of the Scottish mainland (Figure 5.47: A).

In June / August 2012, one puffin was recorded in the Pentland Firth, to the east of Swona (Figure 5.47: B).

During the September / October 2012 survey, three puffins were recorded in offshore waters. Two of these individuals were located in the south-west of the PFOW survey area and one individual was recorded in the south-east (Figure 5.47: C).

Higher numbers of puffins were recorded during the October / November 2012 survey with single individuals widely scattered throughout both inshore and offshore waters. Two groups of two individuals were recorded towards the western boundary of the PFOW survey area (Figure 5.47: D).

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Figure 5.47: Distribution of puffins recorded in the PFOW area in each survey (there are no maps for survey windows where no birds were recorded).

A: May / June 2012 B: June / August2012

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5.2 Abundance estimates and distribution of marine mammal species / groups

All mammal abundance estimates presented in the following tables in the results section are relative, as they do not account for mammals under water at the time of the survey.

5.2.1 Total phocids

5.2.1.1 Abundance estimates

Data presented in Table 5.105 refer to total phocids (including grey seals, common seals and seals not identified to species level). Moderate numbers of phocids were recorded in all survey windows. Numbers peaked in October / November 2012 when the population was estimated at 31,246 (11,240 – 51,251) phocids. All phocids were recorded (mostly at haul out sites) within the near shore area with exception of the October / November 2012 survey, where 96 seals were recorded in the wider area.

Table 5.105: Raw counts, number of sightings, population estimates, confidence limits and precision for total phocids in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug / Oct / 2012 / Mar May Jun Aug Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 64 261 34 81 54 1,063 158 Count WA (2 km) 0 0 0 0 0 96 0 Total 64 261 34 81 54 1,159 158 NSA (500 m) 5 11 7 8 20 38 10 Total WA (2 km) 0 0 0 0 0 1 0 sightings Total 5 11 7 8 20 39 10 NSA (500 m) 1,284 5,063 717 1,974 1,660 22,960 2,983 Population WA (2 km) 0 0 0 0 0 8,285 0 Total 1,284 5,063 717 1,974 1,660 31,246 2,983 NSA (500 m) 64 601 127 439 615 11,772 158 LCL WA (2 km) 0 0 0 0 0 96 0 Total 64 261 34 199 439 11,240 7,174 NSA (500 m) 3,652 11,582 1,687 3,998 2,951 35,726 8,704 UCL WA (2 km) 0 0 0 0 0 24,856 0 Total 3,441 10,941 1,542 3,750 2,881 51,251 158 NSA (500 m) 0.13 0.06 0.17 0.11 0.14 0.03 0.08 Precision WA (2 km) N/A N/A N/A N/A N/A 0.1 N/A Total 0.03 0.01 0.04 0.02 0.02 0.01 0.02 Number of sightings: Number of images that contained marine mammals, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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5.2.1.2 Distribution

In February / March 2012, a large group of seals (+ 31) were recorded on and around the island of Stroma, with a smaller group (3 – 6) recorded on the Calf of Flotta and single seals recorded on the Quanterness Skerry in the Bay of Firth, Holm of Papa and Muckle Quoy around Papa Westray (Figure 5.48: A).

In April / May 2012, large groups of seals (+ 31) were located around the island of Gairsay, while smaller groups (11 – 30) were located on the north of Papa Westray and on Yinstay Skerries off the north-east side of the Orkney Mainland. Further small groups were scattered around the Orkney Islands (Figure 5.48: B).

In May / June 2012, the largest seal group (7 – 10) was located close to St John’s Point on the north-east coast of the Scottish mainland. Smaller groups were located on the island of Swona in the Pentland Firth and on Burray Ness on the island of Burray (Figure 5.48: C).

In June / August 2012, large groups of seals (11 – 30) were located on the island of Stroma, Skerries of Skaigram off South Ronaldsay and Skerry of Vasa off Shapinsay. Smaller groups were recorded off the south end of Eday and off Noup Head on Westray (Figure 5.48: D).

During the August / September survey window, the largest group of seals was recorded off the east coast of Papa Westray near the Holm of Papa, with large groups recorded on remote island west of Eday and on the north coast of Graemsay (Figure 5.48: E), with individual seals also recorded close to the Scottish mainland.

In the October / November 2012 survey, groups of seals were distributed throughout the Orkney archipelago (Figure 5.48: F), with large groups of seals recorded close to Hoston Bay off South Ronaldsay, off the north coast of Fara and on remote islands to the east of Cava. Large groups were also recorded to the east of Gairsay in Russness Bay, on Muckle Green Holm south-east of Eday, by the coast of the Calf of Eday, on the Holm of Faray and Rusk Holm (Figure 5.48: F).

During December 2012 / January 2013, seal numbers decreased compared to the October / November 2012 survey, with the largest group (+ 31) recorded off the north-east of Gairsay. Further large groups (11 – 31) were observed near small islands such as Rusk Holm to west of Fara and along the south-east coast of Stroma (Figure 5.48: G)

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Figure 5.48: Distribution of total phocids recorded in the PFOW area in each survey (there are no maps for survey windows where no phocids were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.2.2 Common seals

5.2.2.1 Abundance estimates

Data presented in Table 5.106 refer to common seals. Low numbers of common seals were recorded in August / September 2012 when the population was estimated at 523 (17 – 1,530 phocids. All common seals were recorded (mostly at haul out sites) within the near shore area.

Table 5.106: Raw counts, number of sightings, population estimates, confidence limits and precision for common seals in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 17 0 0 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 17 0 0 NSA (500 m) 0 0 0 0 1 0 0 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 0 0 0 0 1 0 0 NSA (500 m) 0 0 0 0 523 0 0 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 523 0 0 NSA (500 m) 0 0 0 0 17 0 0 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 17 0 0 NSA (500 m) 0 0 0 0 1,568 0 0 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 1,530 0 0 NSA (500 m) N/A N/A N/A N/A 0.24 N/A N/A Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total N/A N/A N/A N/A 0.04 N/A N/A Number of sightings: Number of images that contained marine mammals, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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5.2.2.2 Distribution

During the August / September 2012 survey window, 17 common seals were recorded together near the coast of the Holm of Papa to the east of Papa Westray (Figure 5.49: A).

Figure 5.49: Distribution of common seals recorded in the PFOW area in each survey (there are no maps for survey windows where no cetaceans were recorded).

A: August /September 2012

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5.2.3 Grey seals

5.2.3.1 Abundance estimates

Data presented in Table 5.107 refer to grey seals which formed the majority of phocids (92 % of total phocids) recorded. Moderate numbers of grey seals were recorded in all survey windows. Numbers peaked in October / November 2012 when the population was estimated at 31, 246 (11, 240 – 51,251) grey seals. All grey seals except in October / November 2012 were recorded (mostly at haul out sites) within the near shore area.

Table 5.107: Raw counts, number of sightings, population estimates, confidence limits and precision for grey seals in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 63 261 22 57 12 1,063 158 Count WA (2 km) 0 0 0 0 0 96 0 Total 63 261 22 0 12 1,159 158 NSA (500 m) 4 11 2 4 8 38 10 Number of WA (2 km) 0 0 0 0 0 1 0 sightings Total 4 11 2 4 8 39 10 NSA (500 m) 1,264 5,063 464 1,389 369 22,960 2,983 Population WA (2 km) 0 0 0 0 0 8,285 0 Total 1,264 5,063 464 1,389 369 31,246 2,983 NSA (500 m) 63 679 22 57 123 11,772 158 LCL WA (2 km) 0 0 0 0 0 96 0 Total 63 261 22 57 91 11,240 7,174 NSA (500 m) 3,733 11,853 1,392 3,315 707 35,726 8,704 UCL WA (2 km) 0 0 0 0 0 24,856 0 Total 3,420 10,941 1,240 2,980 646 51,251 158 NSA (500 m) 0.13 0.06 0.21 0.13 0.29 0.03 0.08 Precision WA (2 km) N/A N/A N/A N/A N/A 0.1 N/A Total 0.03 0.01 0.05 0.03 0.05 0.01 0.02 Number of sightings: Number of images that contained marine mammals, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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5.2.3.2 Distribution

As the majority of phocids recorded were grey seals, the distribution of grey seals is similar to total phocids.

In February / March 2012, a large group of grey seals (+ 31) was recorded on and around the island of Stroma, a smaller group (3 – 6) was recorded on the Calf of Flotta and single grey seals were recorded on the Quanterness Skerry in the Bay of Firth and Muckle Quoy off Papa Westray (Figure 5.50: A).

In April / May 2012, large groups of grey seals (11 – 30) were located on the north of Papa Westray and on Yinstray Skerries off the north-east side of the Orkney Mainland. Further small groups were scattered around the Orkney Islands (Figure 5.50: B).

In May / June 2012, the largest grey seal group (7 – 10) was located close to St John’s Point on the north-east coast of the Scottish mainland. A smaller group was located on Burray Ness on the island of Burray (Figure 5.50: C).

In June /August 2012, large groups of grey seals (11 – 30) were located on the island of Stroma, Skerries of Skaigram off South Ronaldsay and Skerry of Vasa off Shapinsay. A smaller group was recorded off the south off Noup Head on Westray (Figure 5.50: D).

During the August / September 2012 survey window, the largest group of grey seals (3 – 6) and an individual seal was recorded east of Swona, with further small groups recorded along the south coast of Graemsay, west of Torness on Hoy, east of Vasa Loch off Shapinsay, near the Bay of Ham off Rousay and north-east off Westray and Papa Westray (Figure 5.50: E).

In the October / November 2012 survey, grey seal numbers increased compared to previous survey windows and were distributed throughout the Orkney Islands (Figure 5.50: F). Large groups (11 – 30) were recorded close to Hoston Bay off South Ronaldsay, off the north coast of Fara and on remote islands to the east of Cava. Other larger groups were also recorded to the east of Gairsay in Russness Bay, on Muckle Green Holm south-east of Eday and near the Calf of Eday with two large groups recorded west of Eday on the Holm of Faray and Rusk Holm (Figure 5.50:F).

During December 2012 / January 2013, grey seal numbers decreased compared to the October / November 2012 survey, with the largest group (+ 31) recorded most likely at a haul out sites off the north-east of Gairsay. Further large groups (11 – 31) were observed near small islands such as Rusk Holm to west of Fara and along the south-east coast of Stroma (Figure 5.50: G).

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Figure 5.50: Distribution of grey seals recorded in the PFOW area in each survey (there are no maps for survey windows where no phocids were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November

G: December 2012 / January 2013

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5.2.4 Total dolphins and porpoises

5.2.4.1 Abundance estimates

Data presented in Table 5.108 refer to total dolphins and porpoises (including common dolphins, white-beaked dolphins, harbour porpoises and any dolphins / porpoises not identified to species level). Small numbers of dolphins / porpoises were recorded in all survey windows. The highest numbers were recorded in December 2012 / January 2013. Dolphins / porpoises were recorded within the near shore area and wider area.

Table 5.108: Raw counts, number of sightings, population estimates, confidence limits and precision for total dolphins and porpoises in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 2 1 1 0 1 2 6 Count WA (2 km) 3 0 0 5 4 6 2 Total 5 1 1 5 5 8 8 NSA (500 m) 2 1 1 0 1 2 2 Number of WA (2 km) 1 0 0 3 1 2 1 sightings Total 3 1 1 3 2 4 3 NSA (500 m) 40 19 21 0 31 43 113 Population WA (2 km) 263 0 0 438 452 518 209 Total 303 19 21 438 483 561 322 NSA (500 m) 2 1 1 0 1 2 6 LCL WA (2 km) 3 0 0 5 4 6 2 Total 5 1 1 5 5 8 8 NSA (500 m) 100 58 63 0 92 108 340 UCL WA (2 km) 788 0 0 1,051 1,356 1,553 627 Total 818 56 61 949 1,366 1,420 770 NSA (500 m) 0.71 >1 >1 0 >1 0.71 0.41 Precision WA (2 km) 0.58 N/A N/A 0.45 0.5 >1 0.71 Total 0.06 0.23 0.22 0.05 0.05 0.04 0.06 Number of sightings: Number of images that contained marine mammals, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

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5.2.4.2 Distribution

In February / March 2012, a single porpoise / dolphin was located close to the island of Swona in the Pentland Firth and a second individual was located in Hoy Sound off the north- west tip of the Orkney Mainland. Three porpoises / dolphins were recorded in one group in the far north-east corner of the PFOW area (Figure 5.51: A).

In April / May 2012, one porpoise / dolphin was recorded in Taracliff Bay off the south-east side of the Orkney Mainland (Figure 5.51: B).

In May / June 2012, one porpoise / dolphin was recorded close to the eastern side of the island of Stroma (Figure 5.51: C).

In June / August 2012, two pods of two dolphins / porpoises were recorded in the south-west of the PFOW area in the Pentland Firth while a single dolphin / porpoise was recorded in the far north of the survey area (Figure 5.51: D). All individuals were > 3 km from land.

During the August / September 2012 survey a pod of four dolphins / porpoises was recorded north of Melvich > 20 km from the Scottish Mainland and a single dolphin / porpoise was also recorded north of Strathy > 5 km from the Scottish Mainland (Figure 5.51 :E).

In October / November 2012 three dolphins / porpoises were recorded north of Melvich 3 km from the Scottish Mainland, east of Langskaill > 2 km from the coast of Westray, close to shore off the southern tip of Eday with a pod of dolphin / porpoise recorded far west of Skaill on the Orkney mainland, near the boundary for the PFOW survey area (Figure 5.51: F).

During the December 2012 / January 2013 survey window, a small pod of dolphins / porpoises was recorded between South Ronaldsay and South Walls, north of Swona (Figure 5.51: G), with one individual recorded close to the north tip of Stroma (Figure 5.51:G).

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Figure 5.51: Distribution of dolphins / porpoises recorded in the PFOW area in each survey (there are no maps for survey windows where no cetaceans were recorded).

A: February / March 2012 B: April / May 2012

C: May / June 2012 D: June / August 2012

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E: August / September 2012 F: October / November 2012

G: December 2012 / January 2013

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5.2.5 Harbour porpoises

5.2.5.1 Abundance estimates

Data presented in Table 5.109 refer harbour porpoises. Two harbour porpoises were recorded within the near shore area in June / August 2012 where the population was estimated at 175 (2 – 516) individuals. There were no other cetaceans identified as harbour porpoises in the other survey windows.

Table 5.109: Raw counts, number of sightings, population estimates, confidence limits and precision for harbour porpoises in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 0 0 Count WA (2 km) 0 0 0 2 0 0 0 Total 0 0 0 2 0 0 0 NSA (500 m) 0 0 0 0 0 0 0 Number of WA (2 km) 0 0 0 1 0 0 0 sightings Total 0 0 0 1 0 0 0 NSA (500 m) 0 0 0 0 0 0 0 Population WA (2 km) 0 0 0 175 0 0 0 Total 0 0 0 175 0 0 0 NSA (500 m) 0 0 0 0 0 0 0 LCL WA (2 km) 0 0 0 2 0 0 0 Total 0 0 0 2 0 0 0 NSA (500 m) 0 0 0 0 0 0 0 UCL WA (2 km) 0 0 0 525 0 0 0 Total 0 0 0 516 0 0 0 NSA (500 m) N/A N/A N/A 0 N/A N/A N/A Precision WA (2 km) N/A N/A N/A 0.71 N/A N/A N/A Total N/A N/A N/A 0.08 N/A N/A N/A Number of sightings: Number of images that contained marine mammals, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

5.2.5.2 Distribution

In June / August 2012, two harbour porpoises were recorded together in the south-west of the PFOW area > 3 km from land (Figure 5.52: A).

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Figure 5.52: Distribution of harbour porpoises recorded in the PFOW area in each survey (there are no maps for survey windows where no cetaceans were recorded).

A: June / August 2012

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5.2.6 Common dolphins

5.2.6.1 Abundance estimates

Data presented in Table 5.110 refer common dolphins. Low numbers of common dolphins were recorded in the near shore area during the February / March 2012 and December 2012 / January 2013 survey windows, numbers were highest in the latter month. There were no other common dolphins recorded in the other survey windows.

Table 5.110: Raw counts, number of sightings, population estimates, confidence limits and precision for common dolphins in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 1 0 0 0 0 0 5 Count WA (2 km) 0 0 0 0 0 0 0 Total 1 0 0 0 0 0 5 NSA (500 m) 1 0 0 0 0 0 1 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 1 0 0 0 0 0 1 NSA (500 m) 20 0 0 0 0 0 94 Population WA (2 km) 0 0 0 0 0 0 0 Total 20 0 0 0 0 0 94 NSA (500 m) 1 0 0 0 0 0 5 LCL WA (2 km) 0 0 0 0 0 0 0 Total 1 0 0 0 0 0 274 NSA (500 m) 60 0 0 0 0 0 283 UCL WA (2 km) 0 0 0 0 0 0 0 Total 58 0 0 0 0 0 5 NSA (500 m) >1 N/A N/A N/A N/A N/A 0.45 Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total 0.22 N/A N/A N/A N/A N/A 0.1 Number of sightings: Number of images that contained marine mammals, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

5.2.6.2 Distribution

In February / March 2012, one common dolphin was recorded close to Swona (< 3 km from land) in the Pentland Firth (Figure 5.53: A).

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Figure 5.53: Distribution of common dolphins recorded in the PFOW area in each survey (there are no maps for survey windows where no cetaceans were recorded).

A: February / March 2012 B: December 2012 / January 2013

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5.2.7 White-beaked dolphins

5.2.7.1 Abundance estimates

Data presented in Table 5.111 refer white-beaked dolphins. Five white-beaked dolphins were recorded within the near shore area in October / November 2012. White-beaked dolphins were not recorded in any other month.

Table 5.111: Raw counts, number of sightings, population estimates, confidence limits and precision for white-beaked dolphins in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 0 0 0 Count WA (2 km) 0 0 0 0 0 5 0 Total 0 0 0 0 0 5 0 NSA (500 m) 0 0 0 0 0 0 0 Number of WA (2 km) 0 0 0 0 0 1 0 sightings Total 0 0 0 0 0 1 0 NSA (500 m) 0 0 0 0 0 0 0 Population WA (2 km) 0 0 0 0 0 432 0 Total 0 0 0 0 0 432 0 NSA (500 m) 0 0 0 0 0 0 0 LCL WA (2 km) 0 0 0 0 0 5 0 Total 0 0 0 0 0 5 0 NSA (500 m) 0 0 0 0 0 0 0 UCL WA (2 km) 0 0 0 0 0 1,295 0 Total 0 0 0 0 0 1,272 0 NSA (500 m) N/A N/A N/A N/A N/A N/A N/A Precision WA (2 km) N/A N/A N/A N/A N/A 0.45 N/A Total N/A N/A N/A N/A N/A 0.05 N/A Number of sightings: Number of images that contained marine mammals, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

5.2.7.2 Distribution

During the November / December 2012 survey window, a pod of five white-beaked dolphins was recorded far west of Skaill on the Orkney Mainland, near the boundary for the PFOW survey area (Figure 5.54: A).

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Figure 5.54: Distribution of white-beaked dolphins recorded in the PFOW area in each survey (there are no maps for survey windows where no cetaceans were recorded).

A: October / November 2012

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5.2.8 Minke whales

5.2.8.1 Abundance estimates

Data presented in Table 5.112 refer to minke whales. One minke whale was recorded in the near shore area during the August / September 2012 survey window. Minke whales were not recorded in other months.

Table 5.112: Raw counts, number of sightings, population estimates, confidence limits and precision for minke whales in the PFOW area for each survey.

Survey Window Dec Feb / Apr / May / Jun / Aug Oct / 2012 / Mar May Jun Aug /Sep Nov Jan 2012 2012 2012 2012 2012 2012 2013 NSA (500 m) 0 0 0 0 1 0 0 Count WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 1 0 0 NSA (500 m) 0 0 0 0 1 0 0 Number of WA (2 km) 0 0 0 0 0 0 0 sightings Total 0 0 0 0 1 0 0 NSA (500 m) 0 0 0 0 31 0 0 Population WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 31 0 0 NSA (500 m) 0 0 0 0 1 0 0 LCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 1 0 0 NSA (500 m) 0 0 0 0 92 0 0 UCL WA (2 km) 0 0 0 0 0 0 0 Total 0 0 0 0 90 0 0 NSA (500 m) N/A N/A N/A N/A >1 N/A N/A Precision WA (2 km) N/A N/A N/A N/A N/A N/A N/A Total N/A N/A N/A N/A 0.18 N/A N/A Number of sightings: Number of images that contained marine mammals, Population: Population from design-based estimates, LCL: Lower Confidence Limit, UCL: Upper Confidence Limit, NSA: Near Shore Area (images collected at 500 m on transects spaced 2 km apart), WA: Wider Area (images collected on 2 km grid).

5.2.8.2 Distribution

During the August / September 2012 survey window a minke whale was recorded less than 3 km from land south of Liddel on South Ronaldsay, between South Ronaldsay and Muckle Skerry (Figure 5.55: A).

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Figure 5.55: Distribution of minke whale recorded in the PFOW area in each survey (there are no maps for survey windows where no minke whales were recorded).

A: August / September 2012

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5.3 Numbers recorded and distribution of fish

A few fish were recorded during the aerial surveys. As fish are under water most of the time, these are incidental sightings of a few large fish seen at the surface.

5.3.8.3 Numbers recorded

Two elasmobranch (sharks, rays and skate family) species were recorded in the PFOW area. One porbeagle shark was recorded in the near shore area during the October / November 2012 survey window and one skate / ray was recorded in the wider area during the December 2012 / January 2013 survey window.

5.3.8.4 Distribution

During the October / November 2012 survey window a porbeagle shark was recorded less than 3 km from land south of Liddel on South Ronaldsay, between South Ronaldsay and Muckle Skerry (Figure 5.56: A).

In the December 2012 / January 2013 survey, one skate / ray was recorded in open water to the west of Westray (Figure 5.56: B).

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Figure 5.56: Distribution of fish recorded in the PFOW area in each survey (there are no maps for survey windows where no fish were recorded).

A: October / November 2012 – Porbeagle shark B: December 2012 / January 2013 – Shark / Ray

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5.4 Comparison of Year 1 (2010 / 11) and Year 2 (2012 / 13) aerial surveys

The number of sightings, number of species and total population estimates were compared between the original Year 1 2010 / 11 aerial survey data (APEM 2013a; excluding any later additional image analysis) and the Year 2 2012 / 13 data (Figures 5.57 – 5.59).

Figure 5.57: Total number of sightings (number of images containing animals) recorded across all seven aerial surveys each during the first year 2010 / 11 (excluding any additional analysis) and second year 2012 / 13 aerial surveys in the Pentland Firth and Orkney Waters. Only the species and species groups that were recorded in both years are compared.

2200 2000 Year 1 1800 1600 Year 2 1400 1200 1000 800 600

Total Sightings Total 400 200

0 Total geese Greylag geese Total ducks Common eiders Total divers Fulmars Gannets Total shags cormorants & Shags Total grebes Total waders Total skuas Great skuas Total gulls small Kittiwakes Black-headed gulls Common gulls Total gulls large black-backedLesser gulls Herring gulls Great black-backed gulls Total terns Arctic terns Total auks Total guillemots & razorbills Black guillemots Puffins Phocids &Total dolphins popoises White-beaked dolphins

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Figure 5.58: Comparison of the number of species recorded across all seven aerial surveys during the first year 2010 / 11 (excluding any additional analysis) and second year 2012 / 13 aerial surveys in the Pentland Firth and Orkney Waters.

10 Total number of species number Total 5

0 First year 2011 Second year 2012

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Figure 5.59: Total population estimates and 95% confidence limits of species / species groups recorded across all seven aerial surveys each during the first year 2010 / 11 (excluding any additional analysis) and second year 2012 / 13 aerial surveys in the Pentland Firth and Orkney Waters. Only the species and species groups that were recorded in both years are compared.

300,000 280,000 Year 1 260,000 240,000 Year 2 220,000

200,000 180,000 160,000 140,000 120,000 100,000 80,000

Population estimate Population 60,000 40,000 20,000

0 Total geese Greylag geese Total ducks Common eiders Total divers Fulmars Gannets Total shags cormorants & Shags Total grebes Total waders Total skuas Great skuas Total gulls small Kittiwakes Black headed gulls Common gulls Total gulls large Lesser Black-backed gulls Herring gulls Great gulls Black-backed Total terns Arctic terns Total auks Total guillemots & razorbills Black guillemots Puffins Phocids &Total dolphins porpoises White beaked dolphins

Species / species group

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6 DISCUSSION

6.1 Survey summary

This report presents the analysis of data collected across all seven aerial surveys flown in the PFOW area (5,935 km2), with the aim of characterising the use of sea space by birds and marine mammals in the second year. Surveys were undertaken between March 2012 and January 2013 using a stratified survey design. This design aimed to improve the coverage from the first year aerial surveys, and hence the number or species and individuals recorded, in near shore waters (up to 3 km from land).

Design-based estimates of bird and marine mammal abundance were calculated and distributions were presented in relative density maps. Distribution of bird species reflected other distribution maps based on data collected in the Orkney area (e.g. Stone et al. 1995). However, as the survey coverage differs between the Stone et al 1995 surveys and the surveys presented in this report, it was not possible to make a direct comparison of population estimates between these two datasets. Precision was generally high (CV < 0.16) where there were sufficient data; although there were inevitably some situations where abundance was too low for estimates to be made with this target level of precision.

All surveys were completed within the target survey windows, despite challenging environmental conditions. Most surveys were completed within four days, minimising temporal variation as far as possible; the equivalent length of transect would have taken a boat travelling at 10 knots (as per Camphuysen et al. 2004) more than 191 hours (32 days in winter with average day length of six hours) to complete. Images collected were thoroughly scrutinised and rates of agreement between internal and external analysts were high (Appendix III).

6.2 Second year species accounts

For all species (both coastal and pelagic species), the number of birds recorded in the near shore area was greater than the number recorded in the wider area. The main reason for this can be accounted for by the higher survey coverage within the near shore area. A total of 7,696 additional images were analysed in the first 3 km off land (near shore area) compared with the wider area and this higher coverage increased the chance of encounter and therefore the number of birds recorded for each species.

For coastal species such as wildfowl and waders, the majority of birds were recorded within the near shore area. This was expected, as these species breed and feed on or close to land within inshore areas for most of the year, except during times of migration. In contrast, pelagic species (e.g. fulmars, gannets, auks etc.) have wide foraging ranges (Thaxter et al. 2012) and can travel large distances out to sea in search of food. This ability to travel further offshore to feed meant that pelagic species were recorded in the near shore as well as the wider area, although the proportion of birds in each area depended on the time of year and the species concerned. It may be possible that rough sea states during the winter of 2012 / 13 pushed pelagic species closer to shore during the non breeding season, therefore increasing their numbers in the near shore area.

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6.2.1 Wildfowl

Wildfowl (swans, geese and ducks) were recorded all around the Orkney Islands and to a lesser degree along the north coast of Scotland within the near shore area during the second year surveys in the PFOW. Wildfowl were generally recorded in all survey windows and numbers were highest over the winter period especially shortly before the spring migration in the February / March 2012 survey window.

A very small number of mute swans were recorded in the May / June, June / August and October / November 2012 survey windows. Mute swans are an uncommon breeding species but fairly common non-breeder around the Orkney Isles. Two out of the three swans recorded in July (peak estimate in July 73 (3 – 213) birds; CV’ = 0.12) were recorded around South Ronaldsay where they may have been breeding as this species was recorded breeding on South Ronaldsay in 2011 (Orkney Bird Report Committee 2012).

Greylag geese were recorded sporadically over the PFOW area, unsurprisingly always close to land near their feeding and breeding grounds. In the June / August 2012 survey window two large groups (>31 birds) of greylag geese were recorded off in Rousay Sound close to the islands of Rousay and Egilsay; these are likely to have been breeding in these locations, consistent with recent increases of this species documented within Orkney (Trinder et al. 2009; Mitchell et al. 2010). The peak greylag goose population was recorded in the October / November 2012 survey window (9,007 (417 – 17,838) birds; CV’ = 0.01) which ties in with the main autumn migration from Iceland. The number of overwintering greylag geese in Orkney has been gradually increasing since the early 1980s. With increasing numbers of birds choosing to overwinter in Orkney rather than disperse to traditional overwintering areas further south, Orkney has become the most important area in Britain for wintering greylag geese (Churchill et al. 2009).

Very small numbers of shelduck were recorded in the PFOW. The peak record in the February / March 2012 survey window (peak estimate: 60 (3 –V’ 175); C = 0.13) was recorded in the Bay of Ireland on the south – west coast of the Orkney mainland. These shelducks are likely to have come from their European moulting grounds (e.g. Waddensee on the German North Sea coast), where they gather together in huge flocks to collectively moult flight feathers (Svensson et al 2009, RSPB Bird Report 2010). Another small group of shelducks were also recorded in the May / June 2012 survey window within the sea loch of Loch Eriboll on the north – west coast of the Scottish mainland where they are likely to have been breeding. Shelducks were not recorded breeding elsewhere, although they do breed in a range of places in Orkney. They spend much time on land along seashores, lakes and rivers during the breeding season where they would not have been included in this analysis.

Several large flocks of wigeon were recorded over the winter months in the PFOW. As an established wintering species in this area, the last of the wigeon left the area in late April / May 2012 and had returned from their breeding grounds in the Arctic by the time of the survey in November 2012. The peak count was recorded in the February / March 2012 survey window (peak estimate: 4,616 (875 – V’8,357); C = 0.01); groups at this time with > 31 birds were recorded around the Orkney mainland including: Bay of Ireland, Bay of Firth and Deer Sound. Slightly smaller groups were recorded further north in Papa Sound and in the Bay of Cubbigo off Westray. As expected no wigeon were recorded in the survey area

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APEM Final Report 511639 during the breeding season from May - July as wigeon is an uncommon breeding species in the PFOW area.

Small numbers of mallards were recorded over the winter months between November 2012 and January 2013. Mallards are a resident species in Orkney and are closely connected with land where they feed in still and shallow waters less than 1 m deep; at coastal sites, the water is shallow, fairly sheltered and within sight of land. Mallards were not recorded during the breeding season as at this time of year they can retreat to breeding sites some distance from water (BWPi 2004).

Eider are a common resident species in Orkney and they were recorded in all seven aerial surveys. The largest numbers were recorded over the winter months, the peak population of eiders (peak estimate: 6,462 (500 – V’12,424); C = 0.01) was made in the February / March 2012 survey window, with lower estimates into April, May and July. The February / March estimate likely reflects pre-breeding flocks of birds, with lower estimates into summer reflecting movement to nesting colonies on shore. Common eider distribution is generally associated with inshore habitats, reflecting preferences for benthic mollusc prey (Snow & Perrins 1998).

The majority of long-tailed ducks were recorded in aerial surveys between October and March. Long-tailed ducks are a common wintering species around Orkney and have formerly bred around the Orkney Isles. The peak population (peak relative estimate: 3,171 (158 – 6,690); CV’ = 0.02) was made in the February / March 2012 survey window when two large groups (> 31 birds) were recorded in Rysa Sound on the east side of Hoy and in Veantrow Bay on the north side of Shapinsay; lower estimates were made in April and May. The peak estimates recorded in March are likely to have been birds gathering together prior to migration to their Arctic breeding grounds (Orkney Bird Report Committee 2012).

Small numbers of common scoter were recorded in the October / November 2012 survey window; the majority of these birds were recorded in one flock close to Burwick on the south-west coast of South Ronaldsay. Although common scoter did formerly breed in Orkney they are now an uncommon visitor (Orkney Bird Report Committee 2012), and the birds recorded in November 2012 were likely stopping over on their migration south from Scandinavia or Iceland (Wernham et al. 2002).

Small numbers of goldeneye were recorded over the winter between November 2012 to January 2013, two birds were recorded in the April / May 2012 survey window. During the non-breeding season goldeneye winter mainly at sea in shallow inshore waters and during the breeding season the species shows a preference for inland lakes (BWPi 2004). Goldeneye are known to spend the winter and occasionally the summer in the Orkney Isles (Orkney Bird Report Committee 2012).

Red-breasted mergansers were recorded in the winter months between November and March. The recorded population was a similar size in the March and November 2012 aerial surveys (peak relative estimate 605: 66 – V’1,143; C = 0.04), mostly around the islands of Westray, Papa Westray and the south-east Orkney mainland. Although not recorded during the spring and summer months, red-breasted merganser is a fairly common breeding species in the Orkney Isles where they breed along shorelines and at clear inland waters. As red-breasted

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APEM Final Report 511639 mergansers spend much of their time on the coast, at inland lochs and rivers which were not included in the analysis for this report, this may explain why there were no red-breasted mergansers recorded during the breeding season.

6.2.2 Divers

The majority of divers were recorded over the winter months between November and March with very small numbers were recorded during the breeding season. Divers were mostly associated with shallow water areas close to land. Red-throated divers are a fairly common breeding summer visitor in the Orkney Isles where they breed on small inland pools and hilltop lochans. Due to their inland breeding locations, it was not unexpected that higher numbers of red-throated divers were not recorded during the breeding season as this analysis did not include birds on land. In all likelihood, the vast majority of divers not identified to species will have been red-throated divers, as the main confusion species, black-throated divers, are comparatively scarce around the Orkney Isles (Orkney Bird Report Committee 2012) and measurements of unidentified divers were not consistent with great northern diver. Small numbers of great northern divers were recorded in all survey windows except during the June / August and August / September 2012 survey windows. The rpeak population was recorded in the February / March 2012 survey window (peak relative estimate 617: 213 – 1,021; CV’ = 0.04). Great northern divers are uncommon in the summer but are present in the winter; the birds recorded in March 2012 may have been on route to their breeding grounds in Iceland (Svensson et al 2009, Wernham et al. 2002).

6.2.3 Fulmars

Fulmars were the most abundant species in the PFOW and were recorded in all seven survey windows. Although higher numbers of fulmars were recorded within the near shore area than the wider area, fulmars were recorded in the wider area more often than less mobile species e.g. wildfowl, waders and auks. Fulmars are widespread breeders and nest wherever habitat is suitable, with particular importance placed upon Orkney and the north coast of mainland Scotland (Mitchell et al. 2004) including several high density areas designated as SPAs for the species (or its assemblage including fulmars). There are six designated SPAs in the PFOW area for breeding seabird assemblages of which breeding Fulmars are a part of including: Calf of Eday, Copinsay, Hoy, North Caithness Cliffs, East Caithness Cliffs, Rousay and West Westray. Fulmar distribution recorded in all seven surveys during the second year surveys corresponded with these SPA areas.

The peak population of fulmars recorded in the December 2012 / January 2013 survey window (peak relative estimate = 53,384 (42,282 – 64,486) birds) was likely due to sexually immature adults and breeders starting to return to colonies at this time. Although numbers of fulmar recorded were high for all surveys, fewer birds were recorded during the breeding season in April / May, May / June and July 2012; the lowest population was recorded in May / June 2012 at a relative estimate of 12,913 (10,143 – 15,682) birds. A proportion of fulmars in the area would have been either on eggs or with chicks on cliff ledges at the time of the spring and summer surveys which may reflect the drop in numbers recorded at this time.

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6.2.4 Gannets and cormorants / shags

Low to moderate numbers of gannets were recorded in all seven survey windows. Gannets were recorded in very low numbers over the winter prior to the April / May 2012 survey window, consistent with a more southerly distribution during the non-breeding season (although adults may attend colonies from January – November; Wernham et al. 2002). During the breeding season, estimates of between 2,611 and 9,047 gannets were made for the entire survey area; the peak population was recorded in the August / September 2012 survey window (peak relative estimate 9,047: 5,544 – V’12,550; C = 0.01) when adults and juveniles were likely emerging from the colonies.

Northern gannet populations in Scotland (as well as the rest of the UK) have been steadily increasing since 1969 / 70, although the rate of increase between the last two national surveys appears to have slowed (JNCC 2013 website). Birds recorded within the PFOW area may have originated from several gannetries as this species forages over a wide spatial area (mean = 140 km; max = 640 km; BirdLife International 2011 and references therein). Gannets can fly at 65 – 80 km/h, this is a conservative estimate and gives breeding gannets a range of 320 – 480 km from the colony, and non-breeders much more (Nelson 1978). The nearest breeding colony within the PFOW boundary today is the recently occupied cliff site at Noup Head on Westray; gannets nested for the first time at this site in 2003. Since its formation, the gannet colony at Noup Head has continued to increase; one apparently occupied nest was counted during the 2004 / 05 census and 600 apparently occupied nests were recorded at the last count in 2011 (JNCC website). Other breeding sites close by include Sule Stack, Fair Isle and Foula, all within 75 km of the nearest survey area boundary and which combined hold an estimated 7,000 apparently occupied nests (Mitchell et al. 2004). Due to the large foraging ranges of gannets, it is possible that some gannets breeding at Noup Head were foraging in areas outside of the survey area, while gannets from other colonies were foraging within the survey area.

The majority of the total cormorant / shag group were identified as shags (96%) and were recorded between August 2012 and January 2013. The relative peak population of shags in the December 2012 / January 2013 survey window was estimated at 1,341 (71 – 2,845; CV = 0.03) birds. This is likely to be an underestimate of the absolute peak shag population as shags may spend some 41% of their time at sea under water (see Appendix IV). Studies have shown that shags can spend >70% of their time foraging during midwinter (Daunt et al. 2006) which may go some way to explain why higher numbers were recorded by the aerial surveys in the winter months. Shags are non-migratory, but are known to move up to 100 km away from breeding colonies during the winter. Population numbers may fluctuate year to year on exposed coasts, such as those around the PFOW area, as shags show wide annual variation in dispersal patterns which may be linked to the influence of weather on food availability (Galbraith et al. 1986). It is very likely that the number of shags in the area was higher than indicated by the aerial surveys in this report as, like other diving bird species, a proportion of the birds would have been diving under water while foraging at the time of the survey. This potential ‘availability bias’ can be corrected using methods developed by Barlow et al. (1988). As an example, a correction factor to account for availability bias has been developed for shags in the PFOW (see Appendix IV).

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6.2.5 Grey heron

Single grey herons were recorded in the May / June 2012 and in December 2012 / January 2013 survey windows. Grey herons used to breed on Orkney until relatively recently and the species is now a fairly common passage migrant and winter visitor.

6.2.6 Grebes

Small numbers of grebes were recorded during the winter months between March and January, the majority of these grebes were identified a Slavonian grebes (62%). Grebes were absent from the aerial surveys during the breeding season. Slavonian grebes are a fairly common winter visitor to the Orkney Isles, but occur only occasionally in summer (Orkney Bird Report Committee 2012).

6.2.7 Waders

Low to moderate numbers of waders were recorded in all seven surveys. The highest numbers of waders were recorded during the winter months between March and November. As these waders were associated with inter-tidal, coastal or onshore breeding habitats, the chance of encounter was improved by the increased survey effort within the near shore area. The peak population estimate of waders in the February / March 2012 survey window was recorded at 10,395 (518 – 22,956; CV = 0.01) birds. The majority of waders were identified as curlews (61%) while 10% were identified as lapwings and 9% as oystercatchers. Curlews, lapwings and oystercatchers are a common wintering and breeding species in the Orkney Isles (Orkney Bird Report Committee 2012). Numbers were lower in the summer due to their attendance at their breeding grounds on land. There are a large number of other waders (e.g. plover, sanderling, dunlin, godwit, turnstone, redshank etc) which breed and overwinter around the Orkney Isles, but as these birds are strongly associated with land they were not recorded in the aerial surveys.

6.2.8 Skuas

The majority of skuas were identified as great skuas (96%) and these were all recorded in relatively small numbers during the breeding season between May to August. The peak population in the June / August 2012 survey window was estimated at 960 (542 – 1,377; CV’ = 0.03) birds. Great skuas are widespread throughout Orkney (Mitchell et al. 2004), though the vast majority of territories are on Hoy & South Walls. It is not surprising that few great skuas were recorded, as during the breeding season this species is highly territorial and remains close to land. Great skuas do not have to forage far from land as a high proportion of their diet is composed of fish often obtained through piratical behaviour by robbing gulls, terns and other birds as big as gannets of their catches. Great skuas also readily kill and eat smaller birds such as puffins. Great skuas are a migrant species, wintering out at sea in the Atlantic Ocean and regularly reaching North American waters, they may also aggregate in areas during the winter where they can scavenge from fisheries. Two Arctic skuas were recorded in August 2012. Arctic skuas are known to nest at lower densities in Orkney (Mitchell et al. 2004), and this species is in decline (now red-listed under Birds of Conservation Concern: Eaton et al. 2009).

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6.2.9 Gulls

Gulls were recorded all around the Orkney Islands and the north coast of Scotland. Generally the majority of gulls were recorded within the near shore area, although a smaller proportion was recorded in the wider area. Gulls were recorded in all seven survey months, although numbers were higher in the winter months.

Of all the small gulls, kittiwakes were generally the most abundant (51 % of total small gulls) species in the PFOW area. The peak population of kittiwakes was recorded in the July 2012 survey window at a relative estimate of 11,976 (4,606 –V’ 19,345; C = 0.04) birds in the whole area. Common gulls (32 % of total small gulls) were the second most abundant species of small gull identified in the PFOW area, the peak population was recorded in the October / November 2012 survey window at a relative estimate of 7,668 (3,064 – 12,271; CV’ = 0.01). Black-headed gulls were the least encountered small gull species (4% of total small gulls), the peak population of these gulls was recorded in the December 2012 / January 2013 survey window at a relative estimate of 1,577 (79 –V’ 4,013; C = 0.03) birds. The overall low numbers of black-headed gulls recorded was perhaps due to a reduced detection during the breeding season in this study, as this species chiefly breeds inland, often close to wetland habitats such as lakes, rivers and lagoons, etc (Snow & Perrins 1998). Outside of the breeding season this species is more common in coastal habitats (del Hoyo et al. 1996) and tidal inshore waters showing a preference for inlets or estuaries with sandy or muddy beaches, and generally avoiding rocky or exposed coastlines (Snow and Perrins 1998).

Kittiwake abundance gently increased from March to July 2012; this pattern likely reflects the fact that kittiwakes are nomadic across the North Atlantic in winter (Wernham et al. 2002), with substantial breeding colonies reflected by seven SPA designations within the survey area. Abundance of common gulls decreased during the breeding season between March to August; like other gull species, the inflated numbers in during the winter may reflect immigration of common gulls from Scandinavia bolstering numbers in winter (Wernham et al. 2002). Black-headed gulls, by contrast, are generally more dispersive and immigration tends to be to more southerly parts of the UK (Wernham et al. 2002; Malling Olsen & Larsson 2003).

Of all the large gulls, herring gulls were generally the most abundant (64% of total large gulls) species of this group in the PFOW area. The peak population of herring gulls was recorded in the February / March 2012 survey window at a relative estimate of 7,628 (3,828 – 11,427; CV’ = 0.01) birds. Great black-backed gulls (17% of total large gulls) were the second most abundant species of large gull identified in the PFOW area, the peak population was recorded in the December 2012 / January 2013 survey window at a relative estimate of 1,219 (652 –V’ 1,785; C = 0.03) birds. Lesser black-backed gulls (3% of total large gulls) were the least abundant large gull species in the PFOW area, the peak population of these gulls was recorded in the October / November 2012 survey window a relative estimate of 453 (132 – 775; CV’ = 0.05) birds. These results are consistent with the relative distributions of these species as there is approximately double the number of breeding herring gulls to lesser black-backed gulls in Orkney (Mitchell et al. 2004).

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6.2.10 Terns

Small numbers of terns were recorded in the summer months between May to August, 13% of these terns were identified as Arctic terns in July 2012. In the breeding season, the majority of birds recorded are expected to be Arctic terns, as this species dominates relative proportions from local breeding estimates (Mitchell et al. 2004; 97% across Orkney, Sutherland and north Caithness, with 90% in Orkney). The Arctic tern’s breeding ground is in the north, with populations in Britain and Ireland being at the southern edge of its breeding range (Wernham et al. 2002). Arctic terns can breed in higher latitudes than any other tern, mainly in coastal areas and offshore islands on flat grass or shingle areas and on beaches (Wernham et al. 2002). The Arctic tern migration from breeding to wintering areas is the longest known animal migration (Egevang et al 2010). During the non-breeding season Arctic terns can migrate to rich feeding areas as far south on the edge of the Antarctic pack ice (Egevang et al 2010, Wernham et al. 2002). The peak tern estimate recorded in May / June 2012 (5,961; 2,767 – 9,156; CV’ = 0.01) falls short of the approximately 13,500 pairs of terns recorded to be breeding in the area (Mitchell et al. 2004), although recent declines in Arctic tern numbers have been documented since that survey program (e.g. British Birds 2011).

6.2.11 Auks

Auks were the most abundant species group in the PFOW area with a peak population recorded in the May / June 2012 survey window at a relative estimate of 39,223 (23,440 – 55,007) birds. Moderate to high numbers of auks were recorded in all seven surveys reflecting the extensive breeding colonies in the area.

The majority of auks (91% of total auks) were identified as common guillemots or razorbills and the peak population of this group was recorded in the May / June 2012 survey window at a relative estimate of 39,097 (23,314 – 54,880) birds. Low numbers of black guillemots and puffins were also identified. Orkney alone is considered to hold approximately 250,000 breeding auks (common guillemots, razorbills, black guillemots and puffins; Mitchell et al. 2004). Although low numbers of black guillemots were recorded, this species does breed in relatively high concentrations around the coasts of the Pentland Firth and Orkney Waters survey area. As black guillemots breed on rocky shorelines, where they nest in rock crevices, it is likely that a proportion of these birds were on land at the time of the surveys during the breeding season. Furthermore, an unknown proportion of auks would have been foraging beneath the surface of the water when images were collected. This ‘availability bias’ could be corrected post hoc. Black guillemots have been shown to forage within 4 km of the coast around the UK and Iceland, although by contrast, in the NW Territories, Canada, breeding adults rarely foraged close to the colony, and some birds may have been travelling as far as 55 km (BirdLife International 2000). Around Papa Westray, the mean foraging distance of black guillemots has been shown to be 2.4 km away from the colony while birds were also recorded foraging in areas up to 3.9 km away from the colony, but despite this large variation in foraging range, feeding sites were never located further than 1.5 km from the shore (BirdLife International 2000).

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6.3 Marine mammals

6.3.1 Phocids Phocids were mainly recorded at haul-out sites in the PFOW with some sightings recorded in open water. The majority (92% of total phocids) were identified as grey seals while a small proportion (1% of total phocids) were identified as harbour seals. Both grey and harbour seals are listed in Annex II of the EU Habitats Directive. Member states are required to designate SACs (Special Areas of Conservation) for all Annex II species to help maintain population levels at a favourable conservation status. Within the PFOW a SAC has been designated at Faray and Holm of Faray for breeding grey seals and another has been designated at Sanday for Harbour seals. The number of grey seals in Orkney has grown slowly between 2005 – 2010 (SCOS 2011).

Grey seals were recorded in all seven survey windows although they spend most of the year at sea and may range widely in search of prey. The peak population of grey seals was recorded in the October / November 2012 survey window at 31,246 (11,240 – 51,251) seals at this time of year they come ashore to form breeding colonies on rocky shores, beaches, occasionally on sandbanks, and on small largely uninhabited islands. The breeding productivity of grey seals is usually monitored during October / November by recording the pups (SMRU Ltd 2011) at haul out sites. Faray and Holm of Faray SACs support a well established grey seal breeding colony which is the third largest in the UK and 4th largest in the world (SMRU Ltd 2011). Lower numbers of grey seals were recorded in the February / March 2012, April / May 2012 and December 2012 / January 2013 survey windows. Between December and April grey seals haul out at sites for their moulting season; the majority of these seals were located around the island of Stroma, Gairsay, Yinstray Skerries and rocky outcrops south of Westray. During the summer months grey seal distribution is much more dispersed than during the breeding and moulting seasons, between May to August 2012 seals were hauled up between foraging trips at a range of sites between Westray in the north and St John’s point on the Scottish mainland in the south.

6.3.2 Cetaceans

In comparison with phocids, cetaceans were less regularly captured in images. Apart from one minke whale recorded in the August / September 2012 survey window, all cetaceans were identified as dolphins or porpoises with the largest population estimated at 561 (8 – 1,420; CV’ = 0.04) individuals in the October / November 2012 survey window. At this time the majority of dolphins / porpoises were located in the Pentland Firth and offshore to the west of Orkney. Some dolphins / porpoises were identified to species including harbour porpoise, common dolphins and white-beaked dolphins. The majority of dolphins / porpoises recorded were likely to have been porpoises, as this is the most common cetacean in the PFOW area (Evans et al. 2011). Harbour porpoises are resident throughout the year in the UK with peak sightings and near-shore numbers usually recorded during the summer months.

6.4 Comparison of Year 1 (2010 / 11) and Year 2 (2012 / 13) aerial surveys

The original Year 1 2010 / 11 aerial survey data (APEM 2013a; excluding any later additional image analysis) were compared with the Year 2 2012 / 13 data. These data were compared because the same design-based method was used in both of these reports to

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Due to the increased survey coverage the number of sightings of each species was higher in the second year compared with the first (Figure 5.57). The higher coverage as well as continuous technological advances in the digital image process also resulted in more animals being identified to species in the second year surveys compared with the first year (Figure 5.58). A total of 16 new bird species and five new marine mammal species were identified in the second year compared with the original first year surveys. The majority of new bird species were identified as wildfowl and waders and included: mute swans, shelducks, wigeon, long-tailed ducks, goldeneye, mallards, red-breasted mergansers, grey herons, Slavonian grebes, oystercatchers, lapwings, red-throated divers, black-throated divers, great- northern divers, cormorants and Arctic skuas. This enhanced species list was expected as the majority of these species spend most of their time on or close to the coastline, therefore an increase in coverage within 3 km off land was likely to increase the chance of encounter with these species. A total of 5 extra marine mammal species were also recorded in the second year surveys including grey seals, common seals, harbour porpoise, common dolphins and minke whales.

As a result of more images having been collected, confidence limits around population estimates were generally tighter for the majority of species in the second year compared with the first (Figure 5.59). These tighter confidence limits mean that a greater certainty can be placed on the population estimates recorded in the second year. The population estimates of waders and wildfowl tended to be higher in the second year compared with the first. This was most likely due to the increased survey coverage within the first 3 km off land where waders and wildfowl spend the majority of their time. However, for more widespread, pelagic species (e.g. fulmars, gannets, gulls and auks) the population estimates were generally not significantly different from each other as confidence limits overlapped between Year 1 and 2 (Figure 5.59). Overlapping confidence limits may be partly due to the wide confidence limits recorded in the first year (as a result of the smaller number of images analysed), but variation in bird numbers and distribution would also have affected the number of birds recorded in each survey window each year and thus lead to increased confidence limits. Pelagic birds generally have wide foraging ranges and can travel large distances in search of food. Reasons why the numbers of these birds may vary include: inter-annual variation in environmental conditions which may cause fluctuating patterns in food distribution, temporal variation of bird movement (i.e. the timing of the survey in each particular window will have an impact on numbers recorded), inter-annual variation in any fishing activity in the area and any other activity / development both within and beyond the survey boundary may influence distribution patterns between years. Therefore, the number of birds recorded in each survey window each year (particularly for pelagic species) is likely to be influenced by some degree to chance encounter, and to a combination of the variables listed above.

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6.5 Further data analysis

Another approach to data analysis for the second year data is to use model-based estimates of bird abundance; for example General Additive Models (GAMs) were used in the Year 1 Additional Analysis report (APEM 2013b). GAMs are based on environmental covariates and they allow informed predictions to be made of density estimates while taking into account environmental variation. For modelled species, the GAM framework can be used to produce smoothed distribution maps representing predicted bird abundance throughout the survey area. GAMs would also negate any issues that may exist with the stratified sampling regime, as they don’t require that a random collection of images has been collected.

However, sophisticated model-based analysis of this type may require more original count data than the more basic design-based analysis. To meet this potential requirement, additional images were collected concurrently during the second year surveys in the PFOW area. Additional images were collected every 250 m along transects spaced 2 km apart across the whole PFOW area. Thus there is one set of extra images available in the near shore area and seven sets of extra images available in the wider area.

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7 CONCLUSIONS

 Data were presented for seven aerial surveys of the PFOW area which were flown between March 2012 and January 2013 in the second year of surveys. The focus of this report was to enumerate birds at sea; therefore birds recorded on or over land were excluded. Abundance estimates calculated in this report were relative and did not account for birds or mammals under water at the time of the survey; this methodology is consistent with the Year 1 PFOW report.

 Fulmars were the most abundant species in the PFOW area. Peak abundance was recorded in the December 2012 / January 2013 survey window at a relative estimate of 53,384 (42,282 – 64,486) birds.

 Auks were the most abundant species group in the PFOW area with a peak population recorded in the May / June 2012 survey window at an estimated 39,223 (23,440 – 55,007) birds. The majority of these auks (91 % of total auks) were identified as guillemots or razorbills.

 Overall, birds were distributed throughout the PFOW area. Higher numbers of all species were recorded within the high coverage near shore area compared to the lower coverage wider area.

 Phocids were the most abundant marine mammal species group in the PFOW area and the majority were identified as grey seals (92%). The peak population was recorded in the October / November 2012 survey window at an estimated 31,246 (11,240 – 51,251) seals when grey seals were at haul out sites for the breeding season.

 Compared with data collected on a 2 km grid over the whole PFOW area in the first year (2010 / 11), the stratified approach to the second year aerial surveys has enhanced the data set. Advantages of increasing the survey coverage in the near shore area includes 1) increased species list recorded by aerial surveys in the area, 2) increased number of birds recorded for the majority of species, 3) improved survey precision and 4) generally tighter confidence limits around relative population estimates.

 Population estimates for pelagic species (e.g. fulmars, gannets, gulls and auks), were not significantly different between the first and second year aerial surveys in the PFOW area as confidence limits overlapped.

 Bird numbers will change from survey to survey due to: inter-annual variation in environmental conditions which may cause fluctuating patterns in food distribution, diurnal variation of bird movement (i.e. the timing of the survey in each particular window will have an impact on numbers recorded), inter-annual variation in any fishing activity in the area and any other activity / development both within and beyond the survey boundary may influence distribution patterns between years.

 One alternative approach to the data analysis presented in this report is to use model- based estimates of bird and mammal abundance from General Additive Models 228

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(GAMs) based on environmental covariates. Additional images collected concurrently during the second year surveys in the PFOW area are ready to be analysed for such an analysis if required.

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8 REFERENCES

APEM (2012a). Investigation of the utilisation of sea space by seabirds in the Pentland Firth & Orkney Area. APEM Final Survey Report 411122. Scottish Government, January 2012. v2 Final, 96 pp.

APEM (2012b). Pentland Firth and Orkney Waters aerial bird survey: 2010 / 11 additional image analysis. APEM Scientific Report 412052. Report to the Crown Estate. 168pp

Barlow, J., Oliver, C.W. Jackson, T.D. & Taylor B.L. (1988) Harbour porpoise (Phocoena phocoena) abundance estimation in California, Oregon, and Washington: II. Aerial surveys. Fishery Bulletin, 86, 433-444

BirdLife International (2011). http://seabird.wikispaces.com/

Borchers, D.L., Buckland, S. T. & Zucchini, W. (2002). Estimating Animal Abundance: Closed Populations. Springer Verlag, London.

British Birds (2011). www.britishbirds.co.uk/news-and-comment/scotland%e2%80%99s- seabird-still-struggling

BWPi 2004. The birds of the Western Palearctic interactive. OUP Birdguides Ltd.

Camphuysen, C.J., Fox, A.D., Leopold, M.F. & Krag Petersen, I. (2004) Towards standardised seabirds at sea census techniques in connection with environmental impact assessments for offshore windfarms in the UK. COWRIE report; Royal Netherlands Institute for Sea Research, Texel.

Canty, A. & Ripley, B. (2010). Boot: Bootstrap R (S-Plus) Functions. R package version 1. 2-43.

Churchill. G., Fairclough. K & Thorne. R. (2009). Orkney Greylag Goose Feasibility Project 2008/09. Scottish Natural Heritage Commissioned Report No.377

Daunt, F., Afanasyev, V., Silk, J.R.D. & Wanless, S. (2006). Extrinsic and intrinsic determinants of winter foraging and breeding phenology in a temperate seabird. Behavioural Ecology & Sociobiology, 59, 381-388.

Dawson, N., Söhle, I.,Wilson, L.J., Dean, B.J., Webb, A. & Reid, J.B. 2008. The numbers of inshore waterbirds using Scapa Flow, Orkney, during the non-breeding season, and an assessment of the area’s potential qualification as an SPA. JNCC Report No. 407.

Del Hoyo, J.; Elliott, A.; Sargatal, J. 1996. Handbook of the Birds of the World, vol. 3: Hoatzin to Auks. Lynx Edicions, Barcelona, Spain.

Eaton, M.A., Brown, A.F., Noble, D.G., Musgrove, A.J., Hearn, R., Aebischer, N.J., Gibbons, D.W., Evans, A. & Gregory, R.D. (2009). Birds of Conservation Concern 3: the

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APEM Final Report 511639 population status of birds in the United Kingdom, Channel Islands and the Isle of Man. British Birds 102: 296-341.

Efron, B. & Tibshirani, R.J. (1993). An Introduction to the Bootstrap. Chapman & Hall, London.

Elliott, J.M. (1977). Some methods for the statistical analysis of samples of benthic invertebrates. Freshwater Biological Association, Scientific Publication no. 25.

Enstipp, M.R., Daunt, F., Wanless, S., Humphreys, E., Hamer, K.C., Benvenuti, G. & Grémillet, D. (2006) Foraging energetics of North Sea birds confronted with fluctuating prey availability. In Top predators in marine ecosystems: their role in monitoring and management. (eds) I.L. Boyd., S. Wanless & C.J. Camphuysen. Cambridge University Press, Cambridge, UK. pp. 191-210.

Egevang, C.,Stenhouse, I.J., Philips, R.A., Petersen, A., Fox, J.W. & Silk, J.R.D. (2010). Tracking of Arctic terns Sterna paradisaea reveals longest animal migration. PNAS, 107 (5), 2078 – 2081.

Evans, P.G.H., Baines, M.E. & Coppock, J. (2001). Abundance and behaviour of cetaceans and basking sharks in the Pentland Firth and Orkney Waters. Report by Hebog Environmental Ltd & Sea Watch Foundation. Scottish Natural Heritage Commissioned Report No. 419.

Galbraith, H., Baillie, S.R., Furness, R.W. & Russell, S. (1986). Regional variations in the dispersal patterns of Shags Phalacrocorax aristotelis in northern Europe. Ornis Scandinavica, 17, 68-74.

Malling Olsen, K. & Larsson, H. (2003) Gulls of North America, Europe, and Asia, Princeton University Press.

McSorley, C.A., Dean, B.J., Webb, A & Reid, J.B. (2003) Seabird use of waters adjacent to colonies Implications for seaward extensions to existing breeding seabird colony Special Protection Areas. JNCC Report No. 329.

Mitchell, C., Griffin, L., Trinder, M. & Newth, J. (2010). The population size of breeding greylag geese Anser anser in Scotland in 2008/09. Scottish Natural Heritage Commissioned Report No. 371.

Mitchell, P.I., Newton, S.F., Ratcliffe, N. & Dunn, T.E. (Eds). (2004). Seabird Populations of Britain and Ireland: results of the Seabird 2000 census (1998-2002). Published by T. and A.D. Poyser, London.

Orkney Bird Report Committee (2012). Orkney Bird Report. The Orcadian, Kirkwall, Orkney KW15 1DW.

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R Development Core Team (2010). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, http://www.R-project.org/.

Reid, J.B., Evans, P.G.H., & Northridge, S.P. (2003). Atlas of Cetacean distribution in north-west European Waters. Joint Nature Conservation Committee, Peterborough.

RSPB Bird Reports (2010) http://www.visitorkney.com/birdreports/birdreports.asp. Accessed July 2012.

SCOS (2011). Scientific advice on matters related to the management of seal populations: 2011. Natural Environment Research Council commissioned report.

SMRU Ltd (2011). Utilisation of space by grey and harbour seals in the Pentland Firth and Orkney waters. Scottish Natural Heritage Commissioned Report No. 441.

Snow, D.W. & Perrins, C.M. (1998). The birds of the western Palearctic, Concise edition. Oxford University Press.

Stone, C.J., Webb, A., Barton, C., Ratcliffe, N., Reed, T.C., Tasker, M.L., Camphuysen, C.J. & Pienkowski, M.W. (1995). An atlas of seabird distribution in north-west European waters. Peterborough, UK.

Svensson, L., Mullarney, K., & Zetterström, D. (2009). Collins Bird Guide. Bonier Fakta. Stockholm.

Thaxter, C.B. & Burton, N.H.K. (2009). High Definition Imagery for Surveying Seabirds and Marine Mammals: A Review of Recent Trials and Development of Protocols. British Trust for Ornithology Report Commissioned by Cowrie Ltd.

Thompson, S.K. (2012). Sampling 3rd ed. John Wiley & Sons Inc. New Jersey, USA.

Trinder, M., Mitchell, C. & Bowler, J. (2009). An assessment of the status of the native Greylag Goose (Anser anser) population in Scotland and an analysis of future trends based on population modelling. Wildfowl & Wetlands Trust report to Scottish Natural Heritage. Slimbridge, UK. 30pp.

Wanless, S., Harris, M.P. & Morris, J.A. (1991). Foraging range and feeding locations of Shags Phalacrocorax aristotelis during chick rearing. Ibis, 133, 30-36.

Wernham, C., Siriwardena, G.M., Toms, M., Marchant, J., Clarke, J.A. & Baillie, S. (eds.) (2002). The Migration Atlas: Movements of the Birds of Britain and Ireland. T. & A.D. Poyser, London.

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9 APPENDIX I – JNCC BIRD GROUPS

No. JNCC Code Grouping Species Code Species 1 Wildfowl species 1520 Mute swan 2 2269 Goose species 1610 Greylag goose 3 1730 Shelduck 4 1790 Wigeon 5 1860 Mallard 6 95018 Seaduck species 2060 Common eider 7 2020 Long-tailed duck 8 2180 Goldeneye 9 2210 Red-breasted merganser 10 20 Red-throated diver 11 95003 Divers 30 Black-throated diver 12 40 Great Northern diver 13 220 Fulmar 220 Fulmar spp. 14 710 Gannet 710 Gannet spp. 15 800 Shag 95009 Cormorant / shag species 16 720 Cormorant 17 1220 Heron species 1220 Grey heron 18 95004 Grebe species 110 Slavonian grebe 19 4500 Oystercatcher 20 5659 Wader species 5410 Curlew 21 4930 Lapwing 22 5690 Great skua 95031 Skua species 23 5670 Arctic skua 24 6020 Kittiwake 25 94003 Small Gull species 5820 Black-headed gull 26 5900 Common Gull 27 5910 Lesser Black-backed Gull 28 95034 Large Gull species 5920 Herring Gull 29 6000 Great Black-backed Gull 30 95037 Tern species 6160 Arctic tern. 31 6340 Common guillemot 32 6360 Razorbill 95040 Auk species 33 6380 Black guillemot 34 6540 Puffin 35 70010 Grey seal 71000 All Phocids (e.g. seals) 36 70020 Harbour seal 37 82410 All porpoises 82410 Harbour porpoise 38 82540 Common dolphin 8200 All dolphins 39 82520 White-beaked dolphin

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10 APPENDIX II – LATIN NAMES OF SPECIES RECORDED

Common name Latin name Porbeagle shark Lamna nasus Mute swan Cygnus olor Greylag goose Anser anser Shelduck Tadorna tadorna Wigeon Anas penelope Common eider Somateria mollissima Long-tailed duck Clangula hyemalis Goldeneye Bucephala clangula Red-breasted merganser Mergus serrator Great Northern Diver Gavia immer Fulmar Fulmarus glacialis Gannet Morus bassanus Shag Phalacrocorax aristotelis Grey heron Ardea alba Slavonian Grebe Podiceps auritus Oystercatcher Haematopus ostraleaus Curlew Numenius arquata Great skua Stercorarius skua Kittiwake Rissa tridactyla Black-headed gull Chroicocephalus ridibundus Common Gull Larus canus Lesser Black-backed Gull Larus fuscus Herring Gull Larus argentatus Great Black-backed Gull Larus marinus Arctic tern Sterna paradisaea Common guillemot Uria aalge Razorbill Alca torda Black Guillemot Cepphus grille Puffin Fratercula arctica Grey seal Halichoerus grypus Harbour porpoise Phocoena phocoena Common dolphin Delphinus delphis White-beaked dolphin Lagenorhynchus albirostri Minke whale Balaenoptera acutorostrata

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11 APPENDIX III – QA RESULTS

Number of birds and % of Number of species identified by BTO if not in Survey Species agreement agreement with APEM between APEM and BTO 1 Black-headed Gull 1 (100%) N/A Common Eider 14 (100%) N/A Common Gull 4 (100%) N/A Curlew 39 (100%) N/A Diver species 3 (100%) N/A Fulmar 154 (99%) 2 Black-backed gull species (1%) Gannet 2 (100%) N/A Great Black-backed Gull 15 (100%) N/A Great Northern Diver 7 (100%) N/A Greylag Goose 25 (100%) N/A Guillemot/Razorbill 52 (100%) N/A Herring Gull 29 (91%) 2 Common Gulls (6%), 1 Kittiwake (3%) Kittiwake 24 (100%) N/A Lesser Black-backed Gull 1 (100%) N/A Oystercatcher 7 (100%) N/A Shelduck 1 (100%) N/A Wigeon 29 (100%) N/A 2 Common Eider 19 (100%) N/A Common Gull 4 (100%) N/A Curlew 3 (100%) N/A Diver species 1 (100%) N/A Fulmar 62 (100%) N/A Gannet 8 (100%) N/A Great Black-backed Gull 5 (100%) N/A Great Northern Diver 1 (100%) N/A Greylag Goose 3 (100%) N/A Guillemot/Razorbill 35 (100%) N/A Herring Gull 7 (87.5%) 1 Common Gull (12.5%) Kittiwake 40 (100%) N/A 3 Black-headed Gull 1 (100%) N/A Common Eider 3 (100%) N/A Common Gull 1 (50%) 1 Herring Gull (50%) Fulmar 46 (96%) 2 Kittiwakes (4%) Gannet 6 (100%) N/A Great-Black-backed Gull 1 (100%) N/A

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Great Skua 1 (100%) N/A Greylag Goose 2 (100%) N/A Guillemot 52 (100%) N/A Guillemot/Razorbill 90 (96%) 4 Kittiwakes (4%) Herring Gull 8 (100%) N/A Kittiwake 30 (100%) N/A Long-tailed Duck 2 (100%) N/A Oystercatcher 0 (0%) 2 Tern species (100%) Razorbill 2 (100%) N/A Tern species 22 (100%) N/A 4 Arctic Tern 10 (100%) N/A Black Guillemot 6 (86%) 1 Unknown Bird (17%) Common Eider 7 (100%) N/A Common Gull 9 (100%) N/A Fulmar 78 (100%) N/A Gannet 29 (100%) N/A Great Black-backed Gull 4 (100%) N/A Great Skua 9 (100%) N/A Greylag Goose 32 (100%) N/A Guillemot 11 (100%) N/A Herring Gull 5 (100%) N/A Kittiwake 53 (100%) N/A 5 Black Guillemot 2 (100%) N/A Black-headed Gull 2 (100%) N/A Commic Tern 0 (0%) 1 Little Gull (100%) Common Eider 3 (100%) N/A Cormorant 2 (100%) N/A Fulmar 42 (100%) N/A Gannet 31 (100%) N/A Great Black-backed Gull 1 (100%) N/A Great Skua 1 (100%) N/A Greylag Goose 7 (100%) N/A Guillemot 1 (100%) N/A Herring Gull 3 (60%) 2 Kittiwakes (40%) Kittiwake 18 (100%) N/A Shag 8 (100%) N/A 6 Black Guillemot 5 (56%) 4 Long-tailed ducks (44%) Black-headed Gull 1 (100%) N/A Common Eider 30 (100%) N/A Common Gull 38 (100%) N/A Diver species 1 (100%) N/A

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Fulmar 86 (100%) N/A Gannet 9 (100%) N/A Goldeneye 0 (0%) 4 Auk species (100%) Great Black-backed Gull 6 (100%) N/A Greylag Goose 49 (100%) N/A Guillemot/Razorbill 16 (89%) 2 long-tailed ducks (11%) Herring Gull 11 (100%) N/A Kittiwake 18 (100%) N/A Lapwing 3 (100%) N/A Long-tailed Duck 4 (100%) N/A Mallard 1 (100%) N/A Puffin 3 (100%) N/A Red-breasted Merganser 0 (0%) 2 Mallards (100%) Red-throated Diver 2 (100%) N/A Shag 2 (100%) N/A Wader species 14 (100%) N/A Wigeon 26 (100%) N/A 7 Black Guillemot 4 (100%) N/A Black-headed Gull 7 (100%) N/A Common Eider 9 (100%) N/A Common Gull 38 (100%) N/A Curlew 20 (100%) N/A Fulmar 270 (100%) N/A Great Black-backed Gull 7 (87.5%) 1 Unknown Bird (14%) Great Northern Diver 1 (100%) N/A Grey Heron 1 (100%) N/A Greylag Goose 38 (100%) N/A Guillemot 7 (100%) N/A Guillemot/Razorbill 20 (100%) N/A Herring Gull 15 (88%) 2 Common Gulls (12%) Kittiwake 3 (100%) N/A Lapwing 10 (100%) N/A Mallard 18 (90%) 2 Wigeons (10%) Oystercatcher 6 (100%) N/A Shag 2 (50%) 2 Common Eiders (50%) Wigeon 1 (100%) N/A

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12 APPENDIX IV – AVALABILITY BIAS CORRECTION FACTORS FOR DIVING SHAGS

12.1 Background and Aims

To account for unknown proportions of birds which may be missed during a survey at sea because they were either a) beneath the surface of the water or b) on land at the time of the survey, correction factors can be applied to the raw counts. The following methods illustrate how these sorts of correction factors can be applied to shags in the PFOW surveys.

Long-term census data show a decrease in the number of breeding shags in the UK, 80% of which are located in Scotland. The latest Seabird 2000 census (Mitchell et al 2004) estimates the Orkney shag population at 3,744 individuals. However, due to recent declines in shag populations, this Orkney population may be lower (possibly c 2000 individuals) if a recent decline of 60 % is applied to the Seabird 2000 data (http://jncc.defra.gov.uk/page-2877).

Although the design-based estimates provided in this report are relative estimates of birds at sea and not absolute population estimates, the estimates for shags stipulated in Table 5.42 appear low in comparison to the Seabird 2000 census data. The discrepancy may be partly explained by availability bias due to birds being under water at the time of the PFOW aerial surveys. Section 12.2.1 demonstrates how to correct availability bias for shags in the PFOW surveys in order to calculate absolute abundance of this species at sea. A proportion of shags will also have been on land at the time of the aerial surveys. Although shags have been found to nest in fairly high densities on the north coast mainland and at various locations around Orkney (Mitchell et al. 2004), the low numbers of shags recorded from the PFOW aerial surveys at sea during the breeding season may be expected since breeding shags spend only approximately 30% of the daylight period at sea (Enstipp et al. 2006). Birds on or over land were not analysed for the PFOW surveys, as the aim of the surveys was measure abundance at sea. Section 12.2.2 demonstrates how to correct for the number of shags on land in the PFOW surveys.

Using published dive profile data, we outline two correction factors that can be used to correct for the number of shags under water and the number of shags on land at the time of the PFOW aerial survey in the August / September 2012 survey window.

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12.2 Methods

12.2.1 Proportion of time under water correction factor

Availability bias due to birds diving under water at the time of a survey can be corrected for if species specific dive information is known.

The problem of detecting diving animals is not new and methods have previously been developed to correct marine mammal abundance estimates made during boat and aerial line-transect surveys (Forney & Barlow 1998; Barlow & Taylor 2005). Following Barlow et al. (1988), we determined availability at the water surface bias as follows:

g(0) availability = ( s + t ) / ( s + d ) eqn. 1 where s is the average length of time spent at the surface, t is the window of time during which a bird is recorded, and d is the average dive duration.

For our digital still survey method, the window of time (t) in which a bird could be recorded was calculated as follows:

t = NRP.tS eqn. 2 where NRP is the number of camera release points per survey (for a PFOW survey c.5,887) and tS average shutter speed (1/3000). Therefore t = 1.96.

Shag dive duration (d) was obtained directly from Wanless et al. (1993) and was estimated as 84.4 seconds. The average length of time spent at the surface (s) was calculated using average trip duration and average number of dives per trip from Wanless et al. (1993) and was estimated as 62.0 seconds. The window of time during which a bird was recorded (t) was estimated as 1.96 seconds, using equation 2. Therefore, g(0) was 0.59 for diving shags (based on dives < 30 m).

So, using these dive data, shags on average are ‘available’ at the sea surface for 59% of the time when foraging at sea, and underwater 41% of the time.

12.2.2 Proportion of time spent on land correction factor

When shags are not foraging out at sea they tend to be on land. Shags are visual- pursuit diving foragers and feed predominantly during daylight hours (Wanless & Harris 1997). They have particularly high foraging costs at low sea temperatures because of their poor plumage insulation (Grémillet et al. 1998). Therefore, there are seasonal differences in the amount of time that shags spend out at sea, a higher

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proportion of the daylight hours are spent foraging during the winter compared with warmer months due to poorer foraging conditions and higher foraging costs (Daunt et al. 2006).

Published dive profile data recording the number of daylight hours that shags spend foraging at sea between September to March was extrapolated for other months of the year (Daunt et al. 2006). The August / September 2013 PFOW survey took place in August. Daunt et al. (2006) estimated that shags spend 4h foraging at sea in August which is equivalent to 26% of the available daylight hours at this time of the year.

So, on average shags in August spent 26% of their time foraging out at sea and were on land for 74% (this correction factor does not take into account the amount of time spent travelling between land and foraging site).

12.2.3 Correction factors applied to the shag August / September 2012 data

The correction factors detailed above were applied to shags recorded in the PFOW August / September 2012 survey window (see Table 5.42, section 5.1.20). Data in Table 12.1 show the uncorrected and corrected estimates for shags.

Table 12.1: Proposed population estimate for shags in August / September 2012 using correction factors for shags under water and shags on land.

Correction factor applied Count Population LCL UCL Precision Uncorrected (see Table 5.42) 37 1,137 400 2,213 0.16 Corrected for shags under water 63 1,937 676 3,842 0.13 Corrected for shags under water and shags on land 243 7,470 2,213 14,109 0.06

Once the correction factors had been applied to the August / September 2012 survey data, the shag absolute abundance estimate at sea increased to 1,937 birds. The total shag population estimate increased to 7,470 birds when the numbers on land were corrected for which exceeds the latest Seabird 2000 census figures (Mitchell et al 2004) for the Orkney shag population. Population numbers may fluctuate year to year on exposed coasts, such as those around the PFOW area, as shags show wide annual variation in dispersal patterns which may be linked to the influence of weather on food availability (Galbraith et al. 1986).

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12.2.4 References

Barlow, J. & Taylor, B.L. (2005) Estimates of sperm whale abundance in the northeastern temperate Pacific from a combined acoustic and visual survey. Marine Mammal Science, 21, 429-445

Daunt, F., Afanasyev, V., Silk, J.R.D. & Wanless, S. (2006) Extrinsic and intrinsic determinants of winter foraging and breeding phenology in a temperate seabird. Behavioural Ecology & Sociobiology, 59, 381-388

Forney, K.A & Barlow, J. (1998) Seasonal patterns in the abundance and distribution of California cetaceans, 1991-1992. Marine Mammal Science, 14, 460-489

Grémillet, D., Tuschy I, Kierspel, M (1998). Body temperature and insulation in diving great cormorants and European shags. Functional Ecology. 12, 386 – 394.

JNCC (2013) Hyperlink to population estimates page on web.

Wanless, S. Corfield, T. Harris, M. P. Buckland, S. T. & Morris, J. A. (1993) Diving behaviour of the shag Phalacrocorax aristotelis in relation to water depth and prey size. Journal of Zoology, 231, 11-25

Wanless, S. and Harris, M.P. (1997) The Shag. BWP Update 1:1 – 13

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