How Parrots Use Broken Beaks to Establish Dominance Among Males

In 2013, a small, malnourished parrot faced dire circumstances in the Arthur’s Pass wilderness of New Zealand’s South Island, missing half of its beak.

Ximena Nelson, a researcher at the University of Canterbury, discovered the bird (known scientifically as nestor notabilis) suffering from a beak injury, likely due to trauma. Recognizing the kea’s endangered status, Nelson’s student opted to rescue him.

This decision would change Bruce’s life forever, setting him on a path to unexpected prominence.

Initially, zookeepers at the Willowbank Wildlife Sanctuary in Christchurch assumed the parrot was female and named her Kati due to the absence of the upper beak. Male keas possess large upper beaks for digging, and it was unclear how a bird with a half-beak could thrive. “I felt he could bite my finger off,” Nelson remarked.

However, DNA tests later confirmed that Kati was a male, and he was renamed Bruce, a title they considered humorously unfit for a parrot.

To everyone’s surprise, Bruce excelled among nine males and three females at Willowbank, swiftly establishing himself as the alpha male of the group, called a “Circus” (the collective term for a group of keas).

Bruce’s success stemmed from his unique adaptation; the absence of his upper beak allowed him to use his lower beak as a weapon, enhancing his competitive edge.

According to Nelson, Bruce’s straight and sharp lower beak proved instrumental in his jousting tactics against rival birds.

Although other males typically weigh over 1 kg and outweigh Bruce, their upper beaks obscure their lower ones, limiting their effectiveness in confrontations.

“Should they attempt to headbutt another bird, the impact would be blunted,” Nelson noted. “Conversely, Bruce charges at his competitors, often almost falling over in his enthusiasm.”

Nelson added, “His jabs are intense; the other birds despise it. When Bruce engages, they quickly take flight.”

Of the 162 aggressive interactions noted over four weeks, Bruce dominated, winning all 36 encounters he participated in.

He also maintained control over four feeders in the enclosure, sometimes enlisting lower-status birds to preen and groom their lower beaks, a behavior unseen in other captive birds.

The research team aimed to investigate how Bruce’s dominance impacted the social hierarchy, discovering that his stress hormone levels were significantly lower than those of his competitors. His alpha status enabled him to engage in aggression far less frequently than required by others.

Researchers assert that besides humans, Bruce represents the first documented case of an injured animal achieving and sustaining alpha male status solely through behavioral innovation.

His story embodies the message that differences need not be disadvantages, and notably, he did not require any beak repairs.

“I genuinely admire Bruce,” Nelson commented. “When it’s time to fight, he puts in his all, fiercely and energetically. Nevertheless, he isn’t a bully.”