ORIGINAL: quiksilver
I've killed a lot of bucks out of scrapes (both natural and man-made)- and have seen them leave scat in the scrapes many times.
Matter of fact, I've got about 10-15 scrapes mapped out in my head right now, that if you went to them, they would certainly be open, active, and probably have some droppings laying around inside the clearing. Conversely, I've seen community-type scrapes go ice-cold overnight. I'd like to blame human contamination, but I think there's more than meets the eye at work.
Scrapes, to me, are the most interesting of all whitetail signposts. If you watch a buck or doe working a scrape over, it's almost as if they're engaging in a complete sensory indulgence - sniffing, licking, peeing, pooping - and thereis definitely more than one gland at work.
They're working the preorbitals on the licking branch, leaving saliva all over it. Then, they're leaving interdigital, anal, and tarsal scents all over the ground.
As far as the poop goes, although I've never specifically read anything on the subject, I'm guessing that deer are leaving scent markers through the anal gland. I know for sure that a lot of canines do this, and it is not very well understood. Animals are more scent and chemically reliant than humans could ever begin to appreciate.
As you watch, it's abundantly clear that they are experiencing a complete olfactory, vomeronasal, nasal, sudoriferous, preorbital and salivary experience. There are multiple chemical cues, scents, hormones and pheromonesat play,I just wish I understood it better.
One thing I've always wondered - regarding breeding: We would all concede that a male whitetail can easily distinguish whether a scrape has, in fact, been visited by a receptive doe. BUT, one thing that I've never really heard anyone discuss (and I think this is fact) - is whether there are chemical cues in the urine/scents/secretions of a NON-RECEPTIVE female that will give the males an outlook into the future to tell how far away she is from coming into estrus - so that they don't have to keep wasting their time coming back until the time is right.
That's not entirely outside the realm of possibility. You have to consider that there were times in history where deer densities were abyssmally low - and it would make sense for these animals to have a built-in system for mapping out when and where does will be ovulating and at what times - so as to not be wandering aimlessly and burning valuable energy.
Good question Quik. I think that shortly before the doe is ready the buck can tell. Hence the chase phase. How far before I'm not sure.
Here is the next question: Can a buck tell if a doe has already been bred? I believe they can because of hormone changes. I can't prove that though.
Another thing you mentioned: a doe visiting a scrape to let the bucks know she is ready. I have never in 33 years of hunting witness this. I have seen does who appear to be on the move searching for a buck but never using a scrape to attract a mate. I've always wondered about that. In the old days it was believed that a buck makes a scrape, a doe pees in it to let them know she is ready , the buck checks the scrape and makes the connection. I'm not so sure thats really how it works.
Something interesting: I helped a friend track a wounded buck one night. It was a yuong buck. He wasn't hurt very bad. His blood trail ( small drops ) led us from one scrape to the next to the next until we determined that he wasn't giong to die and the blood was gone.