The resident ecologist at Norton Mills lake has said that people's lives were put at risk by the person or people who shot to death the geese and swans.
Brian Morland said that police believed a large calibre rifle was used to shoot the birds through the wings and legs.
More top news
A look ahead at the Bank Holiday forecast for the Tyne Tees region.
Do you want to Leave or Remain in the European Union? That's the question facing everyone in the country. But what do young people think?
Remain or Leave? The impact on agriculture in the North East