| During the 20th century the numbers of nesting Sandwich Terns <i>Sterna sandvicensis</i> in The Netherlands have fluctuated heavily. After the collapse in the 19605 the number of breeding pairs increased only slowly and stabilised at a low level. Earlier studies showed that population trends may be related to changes in food availability. Since the Sandwich Tern is a highly specialised piscivorous seabird, which feeds almost exclusively on tour species of fish (herring, sprat, sandeel and greater sandeel), the Sandwich Tern is probably highly vulnerable to changes in the availability of its prey species. To determine the key factors influencing population size the Institute for Forestry and Nature research (IBN-DLO), in co-operation with the... |
