Here's the latest data on the Northern Yellowstone Elk Herd. They're down 24% in just the last year and down over 70% since wolves were reintroduced in 1995. From 2000 to 2011 the NYEH has declined from 14,538 to 4,635.
http://billingsgazette.com/news/nati...a94794397.html
Here's another article from today's Billings Gazette regarding wolf research. Note that the researcher estimates that their wolf population estimates are likely low by as much as 44%.
http://billingsgazette.com/news/stat...6a2dcf7a5.html