In the more than 30 years I have lived in northern Virginia, I have never seen a copperhead, although there have been several reliable copperhead sightings in my neighborhood, the most recent last May. The Smithsonian's National Zoo and Conservation Biology Institute, in a long article has this to say:
The copperhead is the cause of many snakebites yearly but they are
rarely fatal. Bites occur by accidentally stepping on or touching the snake, which tends to be well camouflaged with its surroundings. When touched, the copperhead quickly strikes or remains quiet and tries to flee.
The article talks about the copperhead habitat:
Copperheads prefer terrestrial to semi-aquatic habitats, which include rocky-forested hillsides and various wetlands. They have also been known to occupy abandoned and rotting wood or sawdust piles.
The copperhead hunts by its ability to detect objects that are warmer than its surroundings.
The article says nothing about whether copperheads are sensitive to noise or vibrations transmitted through the ground.
As for my question about reasonable precautions, I am specifically interested in whether simply being noisy is enough to cause them to slither away. If so, is there any difference in behavior between the young and the adults? The young are fully venomous. Obviously, wearing high boots or canvas gaiters and canvas gloves would be effective (as would full armor), but this seems like too much -- and too hot -- for pruning and picking up branches and enjoying my woods.