This month, a jury may decide if the 54-year-old founder of the Galveston Ornithological Society was acting within his rights when he impeded the progress of a bird-stalking predator by means of a bullet. Mr. Stevenson is due to stand trial for felony cat murder. "There are people with the wrong perception of this," he said in his Chevy compact on a stormy morning, driving along a wide beach at Galveston Island's western tip, where curlews, egrets, stilts and herons strut in the tide pools. He stopped at the pilings beneath the San Luis Pass bridge: the scene of the...