Durrell Kapan, right, Lead Researcher of Entomology with the California Academy of Sciences, walks with Lew Stringer, of The Presidio Trust to release silvery blue butterflies, the closest relative to the extinct Xerces blue butterfly, in the Presidio's restored dune habitat in San Francisco, Thursday, April 11, 2024. (AP Photo/Eric Risberg)
Durrell Kapan, Lead Researcher of Entomology with the California Academy of Sciences, holds a pair silvery blue butterflies, the closest relative to the extinct Xerces blue butterfly, before their release in the Presidio's restored dune habitat in San Francisco, Thursday, April 11, 2024. (AP Photo/Eric Risberg)
Jean Fraser, CEO of The Presidio Trust, speaks before the release of silvery blue butterflies, the closest relative to the extinct Xerces blue butterfly, in the Presidio's restored dune habitat in San Francisco, Thursday, April 11, 2024. (AP Photo/Eric Risberg)
People take a closeup view of silvery blue butterflies, the closest relative to the extinct Xerces blue butterfly, after their release in the Presidio's restored dune habitat in San Francisco, Thursday, April 11, 2024. (AP Photo/Eric Risberg)
A silvery blue butterfly, the closest relative to the extinct Xerces blue butterfly, is seen under netting after its release in the Presidio's restored dune habitat in San Francisco, Thursday, April 11, 2024. (AP Photo/Eric Risberg)
Durrell Kapan, Lead Researcher of Entomology with the California Academy of Sciences, displays a silvery blue butterfly, the closest relative to the extinct Xerces blue butterfly, before its release in the Presidio's restored dune habitat in San Francisco, Thursday, April 11, 2024. (AP Photo/Eric Risberg)
Durrell Kapan, Lead Researcher of Entomology with the California Academy of Sciences, talks about the release of silvery blue butterflies, the closest relative to the extinct Xerces blue butterfly, in the Presidio's restored dune habitat in San Francisco, Thursday, April 11, 2024. (AP Photo/Eric Risberg)