When Lynn Rogers arrived back in his Minnesota study area after his month-long lecture tour, he wanted to re-connect with the forest.  So he spent this day looking for dens that his radio-collared bears used some 30 years ago when he recorded den locations with pin-pricks in aerial photos.  He transferred the pin-prick locations to topographic maps on the computer and read the coordinates into a new state-of-the-art Global Positioning System (GPS) donated by Kellie Ross of Monarch Medical of Dallas, Texas.  The GPS Unit helped him overcome his fading memory and find the old dens. 

Many of the dens have disappeared.  Burrows that bears dig in the fall usually collapse the next spring and summer when meltwater and rain saturate the ground.  Dens in brush piles disappear when the brush deteriorates and collapses.  Surface nests disintegrate into piles of litter.  Two large hollow pines that served as dens in decades past were directly in the narrow path of the storm of the century that hit the Boundary Waters Canoe Area Wilderness a few years ago.  A wind of over a hundred miles an hour blew down all the big trees in its path.     

However, the bears also showed Lynn about a dozen rock crevices and caves that should last for centuries.  Lynn revisited a few of these in subsequent winters and sometimes found them occupied.  Now, with the new GPS Unit from Kellie, Lynn is documenting the exact latitude and longitude of each of these dens for posterity. 

The first den was easy.  He knew where it was and simply had to walk to it and record the exact coordinates on the GPS unit.  He had visited it maybe a dozen times over the thirty years and although it was empty this day, he has found it occupied by four different bears over the years.     

The second den was a classic cave that a 450-pound male used in 1970 and a similar male used in 1976.  Lynn knew this den, too, so this visit was again just a matter of recording GPS coordinates for the future.   

The third one was harder.  Decades of forest growth and harvest changed the area beyond recognition.  Lynn had looked for it before, but today, with the approximate location loaded into the GPS, there it was, and he recorded the exact coordinates.  The entrance still looked too small for a bear to enter, as it had in 1971, but at that time it had proven big enough for a mature female and two yearlings to squeeze into.  The interior is spacious--maybe 3 feet wide, 2-3 feet high, and 4-6 feet long.   As a side note, even though that mother of long ago knew about this secure den and a couple others like it, she chose to hibernate one winter in an open brush pile and was killed by a pack of nine wolves.      

The fourth den, also empty, had been used by a mother and yearlings in 1984.  Since then, a balsam fir has grown to sapling size and blocks the entrance.  This den probably will not be reused until the tree grows to maturity, dies, and falls down near the end of this century. 

The fifth den used to be near a logging road that has grown over in the past 30 years.  Now getting to it will be a hike of over three miles roundtrip.  We'll find this one in the future when we try tracking down some of the other rock dens we'd like to find.