Kea Parrot Missing Upper Beak Becomes Alpha Male Through Unique Fighting Style

A kea parrot missing its upper beak has become the dominant male in its captive social group, according to a study published in the journal Current Biology.

The parrot, named Bruce, developed a unique fighting technique to establish dominance and has shown lower stress hormone levels than other males in the group.

Study Overview

A research team from the University of Canterbury, with collaboration from the Institut de Neurociències de la Universitat Autònoma de Barcelona, conducted a four-week observational study at the Willowbank Wildlife Reserve in Christchurch, New Zealand.

The study focused on a group of 12 captive kea, recording 36 combative interactions, feeding behaviors, and social grooming.

Findings on Dominance and Behavior

The study identified Bruce as the alpha male of the group. Key findings include:

• Bruce was undefeated in all recorded dominance interactions with other males.
• He developed a novel fighting technique, described by researchers as "jousting," which involved using his exposed lower beak to strike opponents. This technique displaced other kea 73% of the time.
• Bruce had priority access to feeder stations, reaching them first on 83% of recorded days.
• He received social grooming from four subordinate males.
• Analysis of droppings showed Bruce had the lowest levels of stress hormone metabolites (corticosterone) among males in the group.

Background on Bruce and Kea

Bruce was found in the wild on New Zealand's South Island 12 years ago with the top portion of his beak missing below the nostrils. He was taken into captivity, where he was initially mistaken for a female before genetic testing confirmed he was male. The cause of his beak injury is unknown.

Kea are an endangered species native to New Zealand's South Island and are considered highly intelligent birds with problem-solving abilities. In the wild, their long, curved upper beaks are used for tasks like excavating food from logs.

Researcher Statements and Scientific Context

Lead author Alex Grabham stated that Bruce's case challenges predictions that larger or better-armed competitors should prevail in animal contests.

He noted it represents the first known case of a disabled animal individually reaching and maintaining alpha male status through behavioral innovation.

Professor Ximena Nelson concluded that the case forces a reconsideration of what disability means for behaviorally complex species.

The study references previous observations that physical disability is not a barrier to chimpanzees achieving high social status, citing primatologist Jane Goodall's documentation of a chimpanzee with a paralyzed arm in the 1970s.

Unanswered Questions and Considerations

Researchers note it is unclear whether Bruce could have survived or achieved alpha status in the wild, where conditions differ from captivity. They also stated that group dynamics at Willowbank may change over time, which could affect Bruce's status.