Summer is the peak butterfly season, when warm, sunny weather invites a vibrant array of colorful sulphurs, monarchs, and swallowtails into our gardens, creating a spectacle that excites and entices observers.

A large and diverse garden is often alive with butterflies all summer long. You may think you are seeing the same ones over and over, but the reality is more complicated and more interesting. Most adult butterflies live two to three weeks at most. With common small species like pearl crescents and tailed blues, the first females to emerge in spring or early summer lay eggs that will soon hatch. The caterpillars will grow rapidly and pupate, and another batch of adults will appear; there may be three or more generations in the warm months.

Shorter summers often mean fewer generations. Several species, including some of the swallowtails, may have several broods a year in the Deep South but only one in the North. A 'brood' refers to a group of butterflies that hatch from the same batch of eggs, while a 'generation' is the entire life cycle of a butterfly from egg to adult. And some, including the great spangled fritillary, have a single generation each year regardless of latitude. Of course, the summer butterfly season is also when many migratory southern species push northward. Tropical sulphurs and skippers fly from Mexico into the American Southwest; widespread butterflies like buckeyes and red admirals may reach beyond the Great Lakes. By summer's end, migratory monarchs have reached the northern U.S. and far into Canada, poised for the temperature drop that will send them drifting south again.

Butterflies tend to emerge from their pupas early in the morning. So, keep a lookout earlier in the day for a better chance of seeing a butterfly emerging or drying its wings before it is ready to take flight.