two bay checkerspot butterflies (euphydryas editha bayensis) on goldfield wildflowers; classified as a federally threatened

america april area bay beautiful beauty blooming bright butterfly california chalcedona checkerspot colorful critically day delicate endangered euphydryas editha bayensis flowers fly fragile goldfields grass green insect lasthenia californica natural nature nectar pollen pollinating pollination san francisco season seasonal small specie spring springtime sunny threatened time two vibrant vivid wild wildflowers wildlife wings yellow