Lilacs and eastern tiger swallowtails (Papilio glaucus) seem to blossom and emerge at the same time every year. This makes sense, as these butterflies have a preference for the nectar of pink, purple and red flowers. Male swallowtails (pictured) are yellow, with four black stripes on the front margin of their forewings, while females may be yellow or black, with much more blue on their hind wings. Males emit perfume-like pheromones to attract females as they patrol habitats containing larval host plants (species of Rose and Magnolia families). Prior to landing and mating, male and female swallowtails flutter about each other and are hard to miss at this time of year.