Info for Derb:
Any old farm boy will tell you these were two male rabbits, and somewhere nearby there was a female. Just a mating challenge, sometimes when the spraying isn't enough they will actually attack each other, but usually one is 'muskier' than the other and it never gets there.
This article available online at:
http://www.theatlantic.com/daily-dish/archive/2007/05/bunny-pissing-match/228221/
