Yellow Swallowtails Common
in the San Francisco Bay Area
By Eddie Dunbar
The San Francisco Bay Area has three yellow Swallowtail Butterflies that are common. If there was a 4th it would be the Two-tailed Swallowtail, which it is not so common (It is easily identified by the paired "tails" on each hindwing). The others (the Anise Swallowtail, Western Tiger Swallowtail and the Mountain Swallowtail) have just one pair. In the Bay Area, each can be readily recognized by comparing color richness, wing banding, eye spots, and marginal banding.
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