YOu can't see them, because you don't know how to look for them, and what they will look like when you do see them. In oak, maple, hickory and walnut forests, the leaves lay flat after falling off the trees, and being hit with morning dew a few nights. When deer walk on these, they push the leaves into their tracks, and the ragged edges of the leaves poke up like the points on a crown. Those points cast long shadows in the early morning, or late afternoon light, making them easy to see and follow.
In pine forests, tracks pickup pine needles and scuff them, so that while everything else is flat, where the deer walks, the needles are fluffed up, leaving shadows.
On hard ground, like clay, that takes a shine when baked in the sun, deer tracks leave dull scuff marks.
On damp soils, the deer tracks leave flat surfaces that " Shine " at you when you put them between you and the sun.
In wet ground, you get transfers of mud from the ground to the tops of leaves, or roads, etc., easily seen as a change in color, or a disturbance of the leaves and floor of the forest.
In moss, the deer tracks leave flat shiny spots, just like a human track will leave. This also occurs on rocks covered in lichens.
In tall grasses, the footsteps push the grass blades down, creating a pattern of dark holes in the grass that a trained observer sees easily.
In short grasses, you have to look for the hinges, where the blade of grass has been broken and fluid is pouring out to heal the break. This is often best done by pressing the palm of you hand down on an area of short grass( like on a golf course) to see and " feel " which grass blades bend easier than others. Then with fingers only you differentiate the tracks of a deer, and proceed to read the track to find the next one.
I hope I don't have to explain how to recognize deer tracks in snow. You should understand that there are all kinds of snow, based on the temperature of the air when it falls, and how much relative humidity is in the air. Eskimos are said to have more than 7 different words for snow, because of their need to describe exactly the weather conditions where they live. That same kind of precision is needed to be understood to age tracks in snow, accurately.
That is a brief outline of how you " see " tracks of deer in forests.
Hard Rains do wash away sign, and tracks, and snow covers the tracks up. They may still be there and visible after the snow melts, and that can be useful to know. Wind can erode the ground so that there is no sign or tracks to read.
In a rare case, other animals may be so numerous that their tracks cover up or wipe out the tracks of an animal you are tracking, but that is extremely rare.
A frost can be as frustrating to a tracker as snow, if he is in the middle of tracking a deer, when the temperature drops, and everything becomes covered in frost. He can't see the next track, and his fingertips get frostbite trying to feel the next track in the cold dew and frost.
Falling snow, and blowing snow create their own characteristic ways of aging sign and removing sign.
