What happens When You Shoot A Bird?

In 2008, The Department for Environment, Food and Rural Affairs (DEFRA) performed secret field trials in Borehamwood, Hertfordshire at a cost to the taxpayer of £37,000.
This involved shooting seven birds and destroying three nests to ‘observe’ what would happen.
I think everyone knows what happens if you shoot a bird – it dies.
What right do the Government have to come into our towns and kill birds which are part of the community?