A teenager was shocked to discover a coot with a dart puncturing its neck and alerted the authorities.
Young photographer Jack Barton, 16, was visiting Wimbledon Common with a friend to capture some wildlife with his lens when he spotted the injured bird in Queensmere pond.
He said that it looked like a dart had penetrated the small bird's neck and that its life was in danger, so he called the RSPCA who attended the scene although they could not catch the bird.
A Level student Jack said: "I began to track a pair of coots through my lens and noticed one had something strange through its neck.
"I got closer and realised, to my shock, that the bird had some sort of dart in its neck, protruding through to the other side."
"I was amazed, considering the situation, that the coot was still alive and still seemed to be feeding and preening relatively normally. Its partner was even trying to pull the dart from its neck with its beak."
Jack took photographs of the injured coot and uploaded them onto social networking sites when he returned home later that day.
He spoke to another young photographer who got in touch with the Wimbledon Common park rangers. Jack said that they informed his friend that they were monitoring the coot but there was little they could do.
He said that he was shocked that someone could throw a playing dart into a wild animal.
Jack said: "It pains me to think that the coot has most likely undeservedly died due to its injuries."
The young wildlife enthusiast added: "What really gets to me was the idea that any human being would have the heartlessness and barbarity to do such a thing.
"Who, with any appreciation of our natural world, would think it's acceptable to send a dart through the neck of a bird and put it though any unnecessary suffering? Unfortunately, I know full well there are too many people out there with little appreciation for our natural world."