Before trail cams...
The first trail thing I used was a timer. I don't recall the year. Anyone remember these gadgets? Been a long time ago.
I attached trip wire to other side of trail.
Gadget would record time string was tripped. No pictures, just the time. Primitive nowadays, but that's all we had.
I used mine for predator movement. Setting trip wire lower for Fox & Coon. But a Deer could also trip timer. So numbers varied and I quickly realized it wasn't too useful for my purpose. Gave it to Brother in Law, who used it for scouting Archery Deer movement, way back then.
It was the early 1980's.....I too had these all over the woods, just knew something tall passed through the string and the location of the string would give away the direction of travel. I also would try to scrape up the dirt in the area in an effort to see the size of tracks.
I once strung binder twine over the top of a fence in both directions to discourage deer from jumping over at many of their trails leaving a funnel at a location the fence was down in a effort to get them to walk through my string gadget; however, one of the major flaws was it record the time the first deer passed through, but not how many, which direction the others were traveling or when.
It was the best we had at the time and I spend a lot of hours setting and checking them. I was exited to check them and found the best evidence provided was I could determine the time the first deer of the evening was entering a crop field.
So when Trail cams came along I was eager to start a new habit which I still do today and enjoy very much. Much can be learned most of all there are nice bucks in the woods, they mostly travel at night and I am often setting in the wrong stand on a given day.
On the positive side I never had one stolen....