Derived through Middle French from a Romanic root something like *carnio, flesh.  While one meaning of “carrion” is specifically rotting flesh that is unfit to eat, adjectivally it indicates beings which eat or use that same rotting flesh.  One bird’s squick is another bird’s squee…

• 15.002 and far off there are many carrion birds
• 15.019 and carrion birds are with them hoping for battle

“carrion, n. and adj.” OED Online. Oxford University Press, June 2015. Web. 28 July 2015.