It will also come in handy if the blood is drying up before you get to it . The peroxide will foam up dried blood from days ago.
I keep a squirt bottle of it in my atv box. Watch out though, for some reason the spray mechanisms on the squirt bottles don' t seam to want to last long when using it with peroxide. I found an empty febreeze bottle works best.

If your afraid of " washing" away the blood trail, just mark each confirmed shot with a small peice of white toilet paper.