You may wonder why a big tarpaulin covers part of the north slope above the pond. This is an attempt to prevent the growth of the invasive dog-strangling vine. Once it is been in place for several years, we'll try to plant something else in hopes of preventing the vine from returning in such force. To the left of the slope, the bare soil is home to hundreds of ground-nesting andrenid bees, which emerge at about the same time as the willow flowers.