By Alison Hawkes, Bay Nature
On a mild, sunny afternoon in downtown San Francisco, office workers sit around a plaza eating lunch, for the most part oblivious to the fluttering around them.
Western tiger swallowtail butterflies are attracted to the plaza off Market Street, too, for its flowering cherry trees and London planes, a water fountain and dappled sunshine.
“Right there — look!” said butterfly expert Liam O’Brien, bounding onto the scene as cheery as the yellow, black-striped lepidoptera around him. “It’s the largest butterfly in the county. It looks like it’s going for some nectar source. It’s unusual — what it’s doing in the most hostile part of the city?”
Repeat: What is the tiger swallowtail doing here? This butterfly species normally lives along a riverbank, making use of riparian hardwood trees as egg and caterpillar habitat, and the flowering plants as food for the adults. Downtown San Francisco is a far cry from a riparian corridor — or is it?
Read the complete story at Bay Nature.