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BTO Research Report No. 610 BTO Research Report No. 610 Measuring the interaction between marine features of Special Protection Areas with offshore wind farm development zones through telemetry: second year report Authors Chris B. Thaxter1, Viola H. Ross-Smith1, Nigel A. Clark1, Greg J. Conway1, Helen Wade2, Elizabeth A. Masden2, Mark. M. Rehfisch1, Willem Bouten3 and Niall H.K. Burton1 1 British Trust for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU, UK 2 Centre for Energy and the Environment, Environmental Research Institute, North Highland College – University of the Highlands and Islands (UHI), Ormlie Road, Thurso, Caithness, KW14 7EE 3 Computational Geo-Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Sciencepark 904, 1098 XH Amsterdam, The Netherlands Report of work carried out by the British Trust for Ornithology1 in association with the University of Amsterdam3 on behalf of the Department of Energy and Climate Change March 2012 This document was produced as part of the UK Department of Energy and Climate Change's offshore energy Strategic Environmental Assessment programme. Crown Copyright, all rights reserved British Trust for Ornithology The British Trust for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU Registered Charity No. 216652 CONTENTS Page No. List of Tables ...................................................................................................................................... 3 List of Figures ...................................................................................................................................... 5 EXECUTIVE SUMMARY ........................................................................................................................... 7 1. INTRODUCTION ......................................................................................................................... 9 1.1 Background ................................................................................................................................ 9 1.2 Project aims ............................................................................................................................... 9 2. METHODS ................................................................................................................................ 11 2.1 Field sites ................................................................................................................................. 11 2.2 Wind farm Zones ..................................................................................................................... 11 2.3 The GPS system ....................................................................................................................... 11 2.4 Capturing and attaching devices ............................................................................................ 13 2.5 Nest monitoring ...................................................................................................................... 14 2.5.1 Lesser Black-backed Gulls .......................................................................................... 14 2.5.2 Great Skuas ................................................................................................................. 15 2.5.3 Assessing tag effects – productivity, attendance, and return rates ......................... 16 2.5.3.1 Productivity ................................................................................................................. 16 2.5.3.2 Attendance.................................................................................................................. 18 2.6 GPS Data collection protocols, and post-processing of data ................................................. 18 2.6.1 Breeding and post-breeding distinction .................................................................... 19 2.6.2 Defining trips and calculating trips statistics ............................................................ 19 2.7 Analysis of data ....................................................................................................................... 20 2.7.1 Connectivity with the areas of proposed and consented wind farms ..................... 20 2.7.2 Spatial overlap of home ranges with consented and proposed wind farms ........... 20 2.7.3 Time budgets of birds ................................................................................................ 21 2.7.4 Flight altitudes ............................................................................................................ 21 2.7.5 Formal statistical tests ............................................................................................... 22 3. RESULTS ................................................................................................................................... 23 3.1 Descriptive trip statistics ......................................................................................................... 23 3.1.1 Lesser Black-backed Gull ............................................................................................ 23 3.1.1.1. Annual Variation ......................................................................................................... 23 3.1.2 Great Skua .................................................................................................................. 24 3.1.2.1 Hoy .............................................................................................................................. 24 3.1.2.2 Foula ........................................................................................................................... 24 3.2 Connectivity with the areas of proposed and consented wind farms .................................. 27 3.2.1 Lesser Black-backed Gull ............................................................................................ 27 3.2.1.1 2011 breeding season ................................................................................................. 27 3.2.1.2 Migration .................................................................................................................... 27 3.2.2 Great Skua .................................................................................................................. 29 3.2.2.1 Foula ........................................................................................................................... 29 BTO Research Report No. 610 March 2012 1 Page No. 3.2.2.2 Hoy .............................................................................................................................. 29 3.2.2.3 Migration .................................................................................................................... 30 3.3 Spatial overlap of home ranges with consented and proposed wind farms ........................ 31 3.3.1 Lesser Black-backed Gull ............................................................................................ 31 3.3.2 Great Skua .................................................................................................................. 31 3.3.2.1 Foula ........................................................................................................................... 31 3.3.2.2 Hoy .............................................................................................................................. 31 3.4 Time budgets ........................................................................................................................... 38 3.4.1 Lesser Black-backed Gull ............................................................................................ 38 3.4.2 Great Skua .................................................................................................................. 38 3.4.2.1 Foula ........................................................................................................................... 38 3.4.2.1 Hoy .............................................................................................................................. 39 3.5 Flight heights ........................................................................................................................... 43 4. DISCUSSION ............................................................................................................................. 45 4.1 Overview .................................................................................................................................. 45 4.2 Lesser Black-backed Gulls ....................................................................................................... 45 4.3 Great Skuas .............................................................................................................................. 45 4.4 Effects of wind farms on gulls and skuas ................................................................................ 46 4.5 Concluding comments ............................................................................................................. 46 ACKNOWLEDGMENTS .......................................................................................................................... 47 REFERENCES .................................................................................................................................... 49 BTO Research Report No. 610 March 2012 2 LIST OF TABLES Page No. Table 1 Deployment periods for tags on (a) Lesser Black-backed Gulls and (b) Great Skuas ......... 13
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