Three people reported seeing cougars this week at Jackson Bottom Wetlands Preserve in Hillsboro this week.  The first was on Monday, the second and third were both on Thursday.  Each time, park officials closed the trails.  The trails are back open after state wildlife officials couldn't find any sign of a cougar.  They even used scent-tracking dogs.  Park officials have now posted signs at the park, warning people of a possible cougar, and giving them tips in case they should encounter one.