DianeEG wrote: We had a "flock" roost, one evening about five years ago, in our big old walnut tree. I, too, wondered what was wrong with the leaves until I got close. Simply covered in orange. It's one of the huge thrills of nature. Another time my husband and I were taking a Sunday drive on an narrow old country road with lots of hedge row trees. At the bottom of a hill a huge mass of Monarchs lifted and continued to drift over and around the car. Needless to say, we stopped until the show had moved on but it was awesome.