Fig. 1. Site number
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Site name Kessingland Level Wren Valley Wang Valley Southwold, Buss Creek Southwold, Town Marshes Reydon Marshes Blythburgh, Union Marsh Minsmere Level Sizewell Belts Aldeburgh, Church Fm Marshes Aldeburgh, Town Marshes Aldeburgh, Hazelwood Marshes Snape Marsh Iken Marsh Sudbourne ' A ' Marsh Sudbourne 'B' Marsh Boyton Marshes Cauldwell Hall Marsh Oxley Marsh Shotley Marsh Cattawade Marsh
last two daytime counts, an estimated 700 ducks of six species were recorded. This figure exceeded the peak Minsmere Level count of all duck species. Other night Visits recorded the addition of birds to a site at or after dusk, but these involved much smaller numbers. Evidence was also found during day counts which suggested the heavy use of some grasslands where bird numbers recorded during daytime counts were very low. This again points to night-time activity which could be of significance in evaluating a site's importance, but which would not have been detected during daytime counts. Clearly it would be useful to repeat this survey to establish whether the picture revealed is indicative of a consistent situation. Furthermore, evidence that supports a diffĂŠrence in day/night usage of some grasslands demonstrates the need to investigate the nocturnal behaviour of select species. Such information is essential if accurate ĂŠvaluations of this habitat are to be made. Acknowledgements : Thanks are due to John Shackles (NCC) and Dr Charles Beardall (SWT), for their advice throughout the survey. Also to Rodney West, Mick Wright and Daniel Clark for their assistance in the field work, and all landowners and gamekeepers who kindly gave permission for access onto private land.
References: Nature Conservancy Council. 1989. Guidelines for the selection ofbiological SSSIs NCC, Peterborough. Salmon, D. G., Prys-Jones, R. P. and Kirby, J. S. 1989. Wildfowl and Wader Counts 1988-1989. Wildfowl & Wetlands Trust. w n g h t , M. T. 1989. Suffolk Species Report 1988/89. Suffolk Estuaries Report 3: 31-37.
Tim Holzer, Hill Farm House, Thurlton, Norwich NR14 6QE. 37