The ivory-billed woodpecker and 22 more birds, fish, and other species are officially extinct, according to the U.S. government.
- As NPR reports, it's a rare move for wildlife officials to give up hope on a plant or animal, but scientists say they've exhausted efforts to find these 23.
- A formal announcement from the U.S. Fish and Wildlife Service is expected on Wednesday.
- The factors behind the disappearances vary, according to experts - too much development, water pollution, logging, competition from invasive species, birds killed for feathers, and animals captured by private collectors.
- A Cornell University bird biologist, however, said it's premature to call off the effort specifically for the ivory-billed woodpecker because there's still a chance it could turn up.
Photo Credit: Getty Images