Ducks fighting for food in the city

A large flock of two species of wild ducks have chosen the urban marshland similar to a pond. Despite the abundance of food in the wild, ducks greedily swallow everything that passers-by give to birds.
I deliberately set the camera on the ground, and I walked five meters away, but that was not enough, the birds did not take pieces of bread lying in front of the camera on the ground just ten centimeters from the water. But when I removed the camera from this place they came out of the water to eat everything, the camera a little frightened them.