Hooge Platen Nature Reserve Bird island in a shipping channel
November 13th-17th, Minsmere, SuffolkRene 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
0
100
200
300
1978 1984 1990 1996 2002 2008 2012
bree
ding
pai
rs (n
)
Little tern Avocet Kentish plover
1982
1986
1990
1994
1998
2002
2008
2012
0
4000
8000
Population development of of gulls and terns
Common tern Sandwich tern Blackheaded gull Mediterrenean gull
Breeding pairs and success of Sandwich tern
0
2000
4000
6000
1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 20110
0,4
0,8
1,2
broedparen (n) broedsucces (juv/paar)
Little tern Common tern Sanwich tern0
25
50
75
100
sandeel herring
Prey items fed to the chicks (left) and partners on the breeding site in three species of terns in the same period.
Terns feed mainly on two species of fish
• 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
S a n d e e l
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.