It might just be that the headline is bad and the literature is simply describing vole predation.
Anecdata:
https://www.reddit.com/r/zoology/comments/2bypwd/i_saw_a_gra...
https://www.reddit.com/r/birding/comments/1d1ddnv/birdhouses...
https://www.reddit.com/r/WTF/comments/14715zj/squirrel_eatin... (graphic video)
https://www.reddit.com/r/WTF/comments/dsws02/a_squirrel_eati... (different graphic video)
https://www.youtube.com/watch?v=t9F-lnJtkDA (graphic video eating a mouse)
etc.
The really graphic stuff you tend to see when you look for it is the raptors eating the squirrels. Bird eats squirrel eats bird. The circle of life.