Almost all of my (roughly) four-dozen bucks never needed any tracking at all. Nor does.
But I did lose two, under strange circumstances.
On the first, I shot and "killed" the buck. As I walked up to gut it, he jumped up to run. The bullet had blown up on the upper bone of his foreleg. Okay, so I put the rifle on him to end the story--and got a 4X setting sun through the scope as he disappeared into the mesquite brush. He was seen crippling around, a few days later, and one of the other hunters put an end to the sadness.
The other was what seemed to be a good cross-body heart/lung shot. I saw a bit of blood pop out the off side, and the buck went to his knees. He jumped up and ran, but I didn't figure he could go too far before bleeding out.
I marked the place where I'd seen him go down (always carry toilet paper for that purpose) and started looking for tracks and blood. My father showed up; he was a better tracker than I. No luck. No tracks in the hard soil. No drops of blood for a trail after the original small amount at the site of the shot. After well over an hour we gave up. Too much brush, too many hidey-holes.
So, I dunno. No buzzards ever showed up anywhere in that pasture, from what we saw and from what the rancher later told us.
You're from BATFE? Come right in! I use all your fine products!