Life on the Watershed: Flight Season

Spring is “flight season”—that time of year when we’ll see different colorful butterflies fluttering between native wildflowers as they feed on the nectar before mating, egg laying, and then dying. One species that’s out on the watershed these days—after the larvae have been dormant over the winter—is the endangered Mission blue.  

  

The small coastal Bay Area native was originally named for its proximity to Mission Dolores in San Francisco, and over the years its essential coastal scrub habitat has been lost to development.

Butterfly species in general each have their own specific larval ‘host” plant that is critical for their survival. For Mission blues, it's one of three perennial lupine species, with the summer western lupine species being the most plentiful on the watershed. 

The female lays its eggs on the lupine leaves, stems, flowers and seed pods. The eggs hatch within a few days, and the larvae feed on the plant for the next several weeks. Then they leave to lay dormant in the leaf litter at the base of the plant until the following spring, when they emerge and the cycle begins again. 

Chalcedon checkerspot butterfly

Also in flight at different times throughout the spring and early summer are the more common Monarchs, Tiger swallowtails, Red admirals, Checkerspots, California sisters, and others. The timing depends on individual species schedules, climate, and other variables. 

Monarch butterfly

Besides brightening the landscape, butterflies are fundamental to the entire ecosystem. They pollinate the flowers they’re gleaning nectar from—automatically picking up pollen from the one flower and transmitting it to the next. And—while certain species (like the Monarch) are toxic—many others, along with their eggs and larvae, are food for spiders, birds, reptiles and other small organisms. 

Painted lady butterfly 

The 23,000-acre watershed is a vital refuge for approximately 60 butterfly species as well as other insect, bird, and animal species. We’ll continue to safeguard and restore our lupine for the Mission blues, as well as multiple other native plants that—common or rare—are vital, not only to certain butterfly species, but a whole ecosystem of diverse plant, insect, bird and animal life.