Change cowbell tags to cow_bell? (leaving cowbell tag for musical instrument?)
http://en.wikipedia.org/wiki/Cow_bell being bell on livestock, and
http://en.wikipedia.org/wiki/Cowbell_%28instrument%29 being musical instrument.
I think that since there doesn't seem to be any cowbell musical instruments at e621 yet, I think aliasing cowbell to cow_bell should be good for now.
Updated by Fox2K9