SCOTTISH GOVERNMENT _________________________ YEAR 2: INVESTIGATION OF THE UTILISATION OF SEA SPACE BY SEA BIRDS IN THE PENTLAND FIRTH & ORKNEY AREA 2012 / 13 _________________________ 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 iii APEM Final Report 511639 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 .....................................................................................................