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Hooge Platen Nature Reserve Bird island in a shipping channel November 13th-17th, Minsmere, Suffolk Rene Beijersbergen Westerscheld estuary Keeping an eye on the island Volunteers at work Little Tern breeding in the “safe haven”… Behind the “seawall”…….. The beach, the seawall and the dunes Vegetation of annuals Waterdunen on the estuary Terns breeding on artificial sites Pionieers Hooge Platen breeding pairs (n) 300 200 100 0 1978 1984 1990 Little tern 1996 Avocet 2002 Kentish plover 2008 2012 Population development of of gulls and terns 8000 4000 0 1982 1986 1990 Common tern 1994 Sandwich tern 1998 Blackheaded gull 2002 Mediterrenean gull 2008 2012 Breeding pairs and success of Sandwich tern 6000 1,2 4000 0,8 2000 0,4 0 0 1987 1989 1991 1993 1995 1997 broedparen (n) 1999 2001 2003 2005 broedsucces (juv/paar) 2007 2009 2011 Prey items fed to the chicks (left) and partners on the breeding site in three species of terns in the same period. 100 75 50 25 0 Little tern Common tern sandeel Sanwich tern herring Terns feed mainly on two species of fish Sandeel • • • • Bottomdweller Poor swimmer Local Year round • Live in shallow water (-20 m) • Young and adult share partly same feeding ares Herring • • • • From surface to bottom Fast swimmer Migrator Young and subadults near coast from may-august • Spawning area and nursery geographical separated • Adults live from the Channel till the Norwegian coast Years of poor reproduction by lack of food: • Bodyweight of chicks does not increase over days • Chicks die of starvation • Both parents go out fishing • Increase of predation So what can we conclude….. • Feeding sites are getting more and more unpredictable when the function as a nursery for sandeel and herring is becoming less • Breeding sites (Waterdunen & Zwin) are better off on close distance of nurseries and other spots where small fish aggregrates • Terns are dependant on small fish for the young chicks and bigger fish for themselves • The days when producing a clutch and the first days after hatching seems to be the most vulnerable days.