The mainstream media, especially television, have changed greatly over the last 20 years. As far as news goes, it has not changed for the better.
People argue whether these traditional media are liberal or conservative, but the clearest bias is that "the news" is the product of huge corporations, whose primary goal is not accurate or relevant news, but simply news as entertainment that will bring in the largest profit. Offending the powerful, whomever they may be, is not a profit-maximizing strategy. Should they cover a truly important story, it will disappear in a couple days if viewership or listeners drop off.
Bloggers are increasingly filling the gap -- people who feel strongly and often know the details of matters about which the mainstream media is ignorant.
Television, radio, the large newspapers, the undemocratic status quo, are finding they have to share space with bloggers, many of whom are awful, but others excellent.
Drowning bison is not an earthshaking matter, but there are at least a couple web sources that document it and people who care. As far I can tell, this web page and the Buffalo Field Campaign are the only sources that continuously report news about Yellowstone's bison herd.