They've been descending on Cape May like fun-starved Shriners at some overbooked convention, feasting on the local fare and making a spectacle of themselves before flitting off with nary a goodbye. At least they're a quiet bunch. And not bad to look at, either. Monarch butterflies, their numbers swollen by favorable summer weather, have overtaken New Jersey's southern peninsula this year as they embark on their annual 2,000-mile journey to warmer climes in the mountains of central Mexico. The profusion of color is part of what naturalists predict will be the largest monarch migration through New Jersey and other eastern...