In Reel Nature: America's Romance with Wildlife on Film Gregg Mitman chronicles
this history of Hollywood portrayal of wild animals on film. What I really learned from this is that this battle happened very early on (1910s) and authenticity caved in to theatrics and staged events. Of course, nature can be boring and it was difficult in the 1910s and 1920s to get the big bulky cameras anywhere close enough to view wildlife unobstructed. By the 1930s conservationists willfully overlooked the managed or staged parts of the films on the proviso that it portrayed some version of reality (a lion attacking a wildebeest, is a lion attacking a wildebeest, even if it is on a game farm in California and not Africa) while equally contributing to a sympathetic view of animals. By the 1940s Fairfield Osborn of the New York Zoological Society started to create a nature film series to prompt conservation.
I would only add that several people predated Osborn by 30 years in their appreciation of film and photographic images as beneficial to conservation. In 1913 William Temple Hornaday and T. Gilbert Pearson (of the National Association of Audubon Societies) used a film provided by Edward McIlhenney to lobby Congressmen to pass a plumage ban during Woodrow Wilson's tariff reform. If McIlhenney's name looks familiar it is because he belonged to the family that produced tobacco sauce. Thus he was a well-to-do hunter in the gentleman-sportsman mould who wanted to put the market hunters out of business. He filmed some footage of dead herons and egrets, lost young who would soon die of starvation because their parents had been killed by hunters, and market hunters skinning their pray. The film produced positive results, although it had not been alone responsible for convincing Congress to enact the ban. Hornaday, likewise, used graphic images in his books, most notably Our Vanishing Wildlife (1913). Hornaday placed pictures of dead herons on their nest, and nestlings baking a slow starvation in the hot summer sun in his conservation book. He consciously sought to tug on the heart strings of his readers, challenge their cultural assumptions (i.e. motherhood), and affect the behavior he wanted. Images might not have been solely responsible, but they were an important part of his message. Although he used films rarely over the remainder of his career, he continued to present photographs through stereoptic slide presentations.
As far as Hollywood, Hornaday never warmed to film. He was too old-fashioned and politically conservative to do anything but reject the consumer cultural challenge to Victorian morality. There are some excellent letters from the mid-1920s in which he eggs the Federation of Women's Clubs to boycott and protest movies by Fatty Arbuckle. Although King Kong is some ways a critique of the Hollywoodization of wildlife, I think Hornaday would have pegged it the ultimate nature faking film if he had seen it.