Nearly 1,900 eggs of the threatened silverspot butterfly were laid at the Oregon Zoo's butterfly conservation lab over the past month.
Egg-laying season drew to a close this week. Each egg is no larger than a grain of sand.
Every summer, female silverspots are collected by field biologists with the U.S. Fish and Wildlife Service and U.S. Forest Service and brought to the zoo to lay eggs.
The eggs hatch into tiny larvae, or caterpillars, which are kept safe at the zoo over the winter.
They grow quickly in the spring, then as the weather grows warmer, zoo workers and conservation partners transport the pupae to field sites along the Oregon Coast to begin the cycle anew.
This past summer, nearly 450 Oregon Zoo-reared silverspots were released among the grassy headlands and salt-spray meadows that make up some of the last remaining habitat for the butterfly, according to zoo workers.
The Oregon silverspot butterfly was once common in coastal grasslands from northern California to British Columbia, but has since vanished from all but five sites due to habitat loss and the disappearance of its host plant, the early blue violet.
The silverspot is listed as threatened under the federal Endangered Species Act.
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