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 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 1994 1998 2002

Common tern Sandwich tern Blackheaded gull Mediterrenean gull

2008 2012

Breeding pairs and success of Sandwich tern

6000 4000 2000 0 1987 1989 1991 1993 1995 1997 broedparen (n) 1999 2001 2003 2005 broedsucces (juv/paar) 2007 2009 2011 0 1,2 0,8 0,4

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 S a n d e e l

• • • • Bottomdweller Poor swimmer Local Year round • Live in shallow water (-20 m) • Young and adult share partly same feeding ares

H e r r i n g

• • • • • • 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 ( aggregrates Waterdunen & Zwin ) are better off on close distance of nurseries and other spots where small fish • 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.