KONING FJ (1965) Some notes about the state bird of prey in the in de Amsterdamse Waterleidingduinen. LIMOSA 38 (1): 16-23.

The cause of the decline of the state bird of prey should be partially sought in population-regulating factors outside of the breeding season, the winter quarters. The following factors may have a direct or indirect influence on the bird population in the splendid dunes: 1. Ret slow disappearance of many old Scots pine (Pinus sylvestris). These species provide excellent nesting opportunities for raptors. 2. Ret deforestation. 3. Ret increasing number of visitors to the dunes. 4. The construction of many new roads and canals so that the peace and wildlife disturbed. 5. Ret rising groundwater from flooding. The flora and avifauna have resulting in substantial changes. 6. Ret shooting of raptors. Due to the fact that they sometimes young fazantjes (for hunting) as food. am to determine whether this is indeed a real decline in vim raptor in the state, will take many years to be observed. first must be determined to what extent the normal year in fluktuaties this population occur. Common Kestrel Falco tinnunculus Long-eared Owl Asio otus Eurasian Sparrowhawk Accipiter nisus Little Owl Athene noctua Eurasian Hobby Falco subbuteo

[free pdf] [dutch summary]