THE ESSEX NATURALIST
Journal of the
ESSEX FIELD CLUB
No 16 (New series)
For the year 1998/99
ISSN 0071-1489
Editorial team: Dr Ken Adams, Dr Peter Allen, Dr Jeremy Dagley,
Dr Chris Gibson, Mr Peter Harvey (Technical Editor)
Copyright © Essex Field Club 1999
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or
transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise.
without the permission of the Essex Field Club or the copyright owner.
Information published in this journal may be freely quoted provided that
full acknowledgement is made in the normal manner to both author and journal.
Published by the Essex Field Club
c/o Department of Life Sciences, University of East London, Romford Road, Stratford, London E15 4LZ
Printed by The Book Company, Ipswich