Walnut, a female crane who famously rejected her fellow birds in favor of a human named Crowe, has died.

The white-naped crane died of kidney failure at age 42 last month, according to a Wednesday announcement by the Smithsonians National Zoo in Washington, D.C.

In life, Walnut was more famous than the average crane because of her special relationship with zookeeper Chris Crowe, whom she seemed to consider her mate for close to 20 years.

The Smithsonians National Zoo and Conservation Biology Institute has characterized Walnut as having a crush on Crowe, noting that she never bonded with other birds.

She had chosen me as her mate, Crowe told The Washington Post . We were a big part of each others lives.