Trees bear evidence when mating bucks on the prowl leave telltale signs

BRAINERD, MINN. – At this time of year, the words "buck sign" are tossed around like autumn leaves in a November gale.

The reference here is not to the many orange signs posted along Minnesota highways that warn drivers of possible deer crossings.

Instead, "buck sign" is a term that hunters use to describe antler rubs on small trees, or saplings, and scrapes made in the ground with bucks' hoofs. Both are calling cards, or "signs," made by amorous white-tailed bucks in preparation for the fall breeding season, or rut.

Let's talk about rubs first.

Sometimes called "antler rubs," these are both visual and olfactory signposts left by bucks on saplings during the rut.

While trees with bark "rubbed off" are easily spotted by deer and people, humans are incapable of analyzing the scent components of rubs, and therefore can't fully interpret the message, or sign, a buck is leaving.

Bucks can leave scent on saplings while rubbing trees because they possess specialized glands in their foreheads. This allows other deer visiting the rub to scrutinize data about the rub maker, such as a buck's social status.

Rubs made as the rut approaches are different from rubs made in early September when bucks rub small trees to remove velvet from their antlers.

Rut rubs, for example, begin to show up in earnest in mid-October. Typically, they are much more aggressively made and often do more damage to a tree than earlier rubs that accommodated velvet removal.

Almost always, the biggest, most aggressive rubs are made by mature bucks. Many times, for example, I've seen big bucks rub on small saplings, but I've never seen young bucks rub on large saplings.

Scrapes, meanwhile, like rubs, are made by bucks in attempts to communicate with other deer. Scrapes are spots where a buck has pawed away leaves and grass, exposing bare soil. Most are roughly 2 feet in diameter, but I've seen some as large as 5 feet across. Scrapes are almost always made under overhanging tree branches.

A buck begins a scrape by rubbing his forehead and preorbital (in front of the eye) glands on the overhanging branch. Sometimes he will actually chew on the branch. Then he paws leaves and other debris from the ground under the branch and urinates into the pawed-out area.

White-tailed does visit scrapes too, and often "work" the overhanging branch, but rarely do they paw the ground.

The age structure of a buck population heavily influences the amount of scraping and rubbing a hunter finds in a given area.

Where yearling bucks dominate (which, unfortunately, is the case in most of Minnesota), scraping and rubbing behavior will be minimal. But if there is an abundance of 2-plus-year-old bucks in the population, "buck sign" will be very evident.