Photo via National Zoo.

Sad news from the National Zoo today: Koa, a six-year-old male brown kiwi, died over the weekend.

According to Zoo officials, the bird didn’t have any warning signs of clinical illnesses or other health issue and was found dead in his exhibit the morning of April 26. A preliminary report indicates that the kiwi had a form of cardiac arrest.

Koa was part of the Zoo’s “Meet a Kiwi” demonstration, in which visitors could get up close with the bird and learn more about the Zoo’s conservation efforts through partnerships like the one with New Zealand’s Operation Nest Egg and the Brown Kiwi Survival Plan. In the wild and in captivity, kiwis can live up to 60 years.

The National Zoo was one of the first institutions to hatch a kiwi chick outside of New Zealand, in 1975, a release states. So far, only 16 female and 35 male kiwis live in zoos outside of New Zealand, the National Zoo still has seven kiwis in the Bird House.