BIG BEAR, Calif. (KABC) — A bald eaglet has died about six weeks after he and a sibling were born in a Big Bear nest watched by thousands on livestream video, a local nonprofit organization said.

"We are very sad to say that it looks like Cookie died just a little bit ago," Friends of Big Bear Valley said in a statement Monday morning, adding that hypothermia was likely the cause. "He was up earlier but looked weak; he also seemed less energetic yesterday."

According to the organization, a recent storm soaked the nest and subsequent snow stuck to the feathers of the chicks' mother, Jackie. The growing eaglets were unable to fully fit underneath the mother on Sunday.

"We are mourning with all the rest of you," Friends of Big Bear Valley said. "Nature can be very tough."

The survival rate of bald eagles is 50 percent in their first year.

"We will all be rooting for Simba to stay strong and healthy," the statement said, referring to Cookie's surviving sibling.

DEVELOPING: More details will be added to this report as they become available.