ED,
Since you're a good man, I'm going to let you int some research I have uncovered...
They're NOT under rocks. It just appears that way.
Deer, like those tunnel rats of SE Asia some decades back, have tunnels "everywhere".
Think about it...you're sitting in a woods full of frozen, tinfoil crunchy leaves straining to hear any movement.
You're plauged by squirrels, tufted titmouse birds flipping leaves and hopping around... and you slowly turn to investigate each and every movement, hoping its a deer.
Then suddenly, there stands a deer! out in the middle of 100 yards of open woods, staring right at you... No sound. Nothing. Just standing there.
See what I mean? Ever notice there is a decent size rock somewhere nearby? Uh-huh... that or a big tree bowl.
That is where the entrance/exit to them danged deer tunnels underground lie!
They must have a pretty sophisticated trap door system on em, cause I can never spot the entrance.
There ya have it! Underground tunnels. They have small spy cams too, I'm sure of it so when you dig in your pack for swammich, they pop up outa a nearby tunnel and run off while their buddies all watch and laugh... they probably have DVD's of me!
Dirty li'l buggars