A decade-old treatment plant in San Diego County, Calif., could leave more water in the Colorado River for states facing severe shortages.

© Sandy Huffaker for The New York Times

A decade-old treatment plant in San Diego County, Calif., could leave more water in the Colorado River for states facing severe shortages.

Once widespread in Japan, the colorful birds went from being fairly commonplace in the country to being on the verge of extinction.

Innovative systems to keep ships from hitting North Atlantic right whales are coming into use. The Trump administration is weighing whether they can replace a bedrock protection.

Innovative systems to keep ships from hitting North Atlantic right whales are coming into use. The Trump administration is weighing whether they can replace a bedrock protection.

© Sophie Park for The New York Times

The Sacramento Mountains checkerspot butterfly hasn’t been seen in the wild since 2022. The caterpillar was the last individual in human care.

© Diana Cervantes for The New York Times