It is time to enjoy the visual beauty and fragrances of the blooming crabapple and apple trees, lilac shrubs and lily-of-the-valley, and the taste of freshly gathered and cooked morel mushrooms. The warbler migration is at its peak, and, on a good day an expert might spot 20 species or more. American robin and eastern bluebird parents are busy feeding young nestlings. The first migrating monarch butterflies appear. Nature Notes, from the Minnesota Weatherguide Environment Calendar