Wow, I initially thought that she spontaneously chose her caretaker as a mating partner, but the process was apparently much more involved!

In September 2004, Walnut arrived at NZCBI’s Virginia campus, where scientists regularly breed cranes that have behavioral or physical limitations by using assisted reproduction techniques, including artificial insemination. By observing and mimicking how NZCBI’s male white-naped cranes interacted with their mates during breeding season, bird keeper Chris Crowe gained Walnut’s elusive trust. He pair-bonded with her by flapping his arms in a manner similar to the species’ unison dance, offered her nesting materials and brought her food. Once she was receptive to breeding, Crowe was able to use sperm collected from a male crane to artificially inseminate Walnut without the need for physical restraint.

Really cute though how the caretaker was really also close to her:

“Walnut was a unique individual with a vivacious personality,” Crowe said. “She was always confident in expressing herself, an eager and excellent dancer, and stoic in the face of life’s challenges. I’ll always be grateful for her bond with me. Walnut’s extraordinary story has helped bring attention to her vulnerable species’ plight. I hope that everyone who was touched by her story understands that her species’ survival depends on our ability and desire to protect wetland habitats.”