This stunning book tells the amazing true story of how a zookeeper taught a rare white-naped crane who thought she was human learn to breed, enabling her to help save her species.
“Walnut” was hand-raised by humans after poachers stole her parents from the wild. Walnut ended up imprinting on her humans.
As we learn in the back matter:
“Imprinting is when certain animals align their species identity with their early caretaker(s). It occurs in the first two weeks of life (identifying with ‘parents’) and strengthens if the animals are away from their own species as they mature.”
The Wildlife Center of Virginia points out:
“If young birds imprint on humans, they will identify with humans for life. Reversing the imprinting process is impossible – these birds will identify with humans rather than with their own species for the rest of their lives.”
This was what happened with Walnut. She refused to have anything to do with other white-naped cranes. But they were all related and she was not, so her genes were urgently needed to help carry on the species.
The Associated Press reported in her obituary (!):
“. . . white-naped cranes are considered vulnerable by the International Union for Conservation of Nature. Today, fewer than 5,300 remain in their native habitats in Mongolia, Siberia, Korea, Japan and China due to habitat loss, pollution, nest predation and poaching. And as the offspring of two wild-caught cranes, Walnut’s genes were not represented in U.S. zoos. So convincing Walnut to breed was regarded as a priority.”
Chris Crowe, part of the Smithsonian’s National Zoo and Conservation Biology Institute (NZCBI), dedicated years to getting Walnut to trust him enough so that he could inject her with genetic material that would allow her to lay eggs without a mate. The story details the extraordinary lengths Chris went to in order to convince Walnut she could trust him, including wearing a giant crane costume.
Chris and Walnut
Finally, Walnut was ready, and she went on to have eight chicks. The fertilized eggs were given to other white-napped crane pairs who tended to them as their own.
She died at the age of 42 in 2024, having spent nearly 20 years with Chris. Pincus writes:
“Walnut’s chicks are all grown up, with mates and chicks of their own – carrying on new generations of white-naped cranes.”
There is a great deal of back matter following this heart-warming story, including more about white-naped cranes and Walnut specifically; more about all cranes generally and imprinting; and about Chris and the NZCBI. Sources are listed for further exploration.
Gillian Eilidh O’Mara, “who never tires of looking up” is known for showing the play of light in the background of her illustrations.
Evaluation: Kids (age 6 and over) as well as adults will pour over the fascinating details of the interactions between Walnut and Chris. The story will also help readers learn more about endangered species, and what steps can be taken to protect them.
Rating: 4/5
Published by Candlewick Entertainment, an imprint of Candlewick Press, 2025
Walnut;picture by Chris Crowe / Smithsonian’s National Zoo and Conservation Biology Institute
