Waders on Swansea Bay: Past Trends and Present Usage
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BTO Research Report No. 92 Waders on Swansea Bay: past trends and present usage by S. Warbrick, R.J. Howells & N.A. Clark A report by the British Trust for Ornithology under contract to the Countryside Council for Wales © British Trust for Ornithology The National Centre for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU BTO Research Report No. 92 July 1992 CONFIDENTIAL LIST OF CONTENTS Page No List of Tables ........................................................................................................................ 3 List of Figures............................................................................................................................. 5 Executive Summary ................................................................................................................. 11 1. General Introduction................................................................................................. 13 LONG TERM TRENDS 2. Background to the BoEE .......................................................................................... 15 3. Methods....................................................................................................................... 16 4. Results and Discussion .............................................................................................. 18 4.1 Oystercatcher ........................................................................................................ 18 4.2 Ringed Plover ....................................................................................................... 18 4.3 Grey Plover ........................................................................................................... 20 4.4 Knot....................................................................................................................... 20 4.5 Sanderling ............................................................................................................. 21 4.6 Dunlin.................................................................................................................... 22 4.7 Bar-tailed Godwit ................................................................................................. 22 4.8 Curlew................................................................................................................... 23 4.9 Redshank............................................................................................................... 24 4.10 Turnstone ............................................................................................................. 24 ALL DAY MOVEMENTS AND DISTRIBUTIONS 5. Background ................................................................................................................ 27 6. Methods and Analysis ............................................................................................... 28 7. Results and Discussion .............................................................................................. 29 7.1 Oystercatcher ........................................................................................................ 29 7.2 Ringed Plover ....................................................................................................... 30 7.3 Grey Plover ........................................................................................................... 30 7.4 Knot....................................................................................................................... 30 7.5 Sanderling ............................................................................................................. 30 7.6 Dunlin.................................................................................................................... 31 7.7 Bar-tailed Godwit ................................................................................................. 32 7.8 Curlew................................................................................................................... 32 7.9 Redshank............................................................................................................... 33 7.10 Turnstone ............................................................................................................. 33 BTO Research Report No. 92 July 1992 1 CONFIDENTIAL Page No 8. Overall Conclusions................................................................................................... 35 9. Recommendations for Further Work..................................................................... 37 References ............................................................................................................................... 38 Acknowledgements ................................................................................................................. 40 Tables 41 Figures .......................................................................................................................................43 BTO Research Report No. 92 July 1992 2 CONFIDENTIAL LIST OF TABLES Page No Table 6.1 Description of substrate types on each count area within the study sites...................................................................................... 41 BTO Research Report No. 92 July 1992 3 CONFIDENTIAL BTO Research Report No. 92 July 1992 4 CONFIDENTIAL LIST OF FIGURES Page No Figure 3.1 Locations of the two main roost sites (Blackpill and Neath) within Swansea Bay............................................................... 43 Figure 4.1.1 The Peak Winter Counts of Oystercatcher at Blackpill and the National Indices between 1969 and 1991 .......................... 43a Figure 4.1.2 The Peak Autumn and Spring Counts of Oystercatcher at Blackpill Between 1969 and 1991..................................................... 44 Figure 4.1.3 Variations in the occurrence of Oystercatcher in Swansea Bay in relation to a) season and b) the national index ...................... 45 Figure 4.1.4 Variations in the National Importance of Blackpill for Oystercatcher between 1973 and 1991.............................................. 46 Figure 4.2.1 The Peak Winter Counts of Ringed Plover at Blackpill and the National Indices between 1969 and 1991 ................................... 47 Figure 4.2.2 The Peak Autumn and Spring Counts of Ringed Plover at Blackpill between 1969 and 1991 ..................................................... 48 Figure 4.2.3 Variations in the occurrence of Ringed Plover in Swansea Bay in relation to a) season and b) the national index ...................... 49 Figure 4.2.4 Variations in the National Importance of Blackpill for Ringed Plover between 1973 and 1991............................................. 50 Figure 4.3.1 The Peak Winter Counts of Grey Plover at Blackpill and the National indices between 1969 and 1991............................. 51 Figure 4.3.2 The Peak Autumn and Spring Counts of Grey Plover at Blackpill between 1969 and 1991 ..................................................... 52 Figure 4.3.3 Variations in the occurrence of Grey Plover in Swansea Bay in relation to a) season and b) the national index ...................... 53 Figure 4.3.4 Variations in the National Importance of Blackpill for Grey Plover between 1973 and 1991 ................................................ 54 Figure 4.4.1 The Peak Winter Counts of Knot at Blackpill and the National Indices between 1969 and 1991 ......................................... 55 Figure 4.4.2 The Peak Autumn and Spring Counts of Knot at Blackpill between 1969 and 1991 ..................................................................... 56 BTO Research Report No. 92 July 1992 5 CONFIDENTIAL Figure 4.4.3 Variations in the occurrence of Knot in Swansea Bay in relation to a) season and b) the national index.................................. 57 Figure 4.5.1 The Peak Winter Counts of Sanderling at Blackpill and the National Indices between 1969 and 1991 ................................... 58 Figure 4.5.2 The Peak Autumn and Spring Counts of Sanderling at Blackpill between 1969 and 1991 ..................................................... 59 Figure 4.5.3 Variations in the occurrence of Sanderling in Swansea Bay in relation to a) season and b) the national index.............................. 60 Figure 4.5.4 Variations in the National Importance of Blackpill for Sanderling between 1973 and 1991................................................... 61 Figure 4.6.1 The Peak Winter Counts of Dunlin at Blackpill and the National Indices between 1969 and 1991 ......................................... 62 Figure 4.6.2 The Peak Autumn and Spring Counts of Dunlin at Blackpill between 1969 and 1991 ..................................................................... 63 Figure 4.6.3 Variations in the occurrence of Dunlin in Swansea Bay in relation to a) season and b) the national index.................................. 64 Figure 4.6.4 Variations in the National Importance of Blackpill for Dunlin between 1973 and 1991......................................................... 65 Figure 4.7.1 The Peak Winter Counts of Bar-tailed Godwit at Blackpill and the National Indices between 1969 and 1991 ............................ 66 Figure 4.7.2 The Peak Autumn and Spring Counts of Bar-tailed Godwit at Blackpill between 1969 and 1991 ................................................. 67 Figure 4.7.3 Variations in the occurrence of Bar-tailed Godwit in Swansea Bay in relation to a) season and b) the national index...................................................................................................