Why year after year is there.....

scraps in the exact spots in my fields I hunt.One for sure every year is in same spot and seams to get bigger each year.Last year I swear you could have put 2 good size deer in it.No joke it was really that big.Biggest scrap I've ever seen.Is it territory scrap or rut scrap.It starts in late sept. and keeps getting bigger through the season until around mid nov. or so.It has me and few friends puzzled.Please give your opinions>