Parrots can move along thin branches using ‘beakiation’

Parrots don’t just hang out for fun.

To move along narrow branches, a parrot can hang from a branch with its beak, swing its body sideways and grab hold farther along with its feet. The newly described gait, dubbed beakiation, expands the birds’ locomotive repertoire and underscores how versatile their beaks are, researchers report January 31 in Royal Society Open Science.

Parrots “are specialized for climbing and moving around in the trees,” says biomechanist Michael Granatosky of the New York Institute of Technology in Old Westbury. But, he wondered, “what would happen if you flip a bird upside down or make them go onto the tiniest [branch] possible?”

So Granatosky and colleagues put four rosy-faced lovebirds (Agapornis roseicollis) to the test. Birds placed on a suspended bar just 2.5 millimeters in diameter realized that the best way to shuffle along it was to use their beaks and feet in a cyclical side-swinging motion. The birds traveled 10 centimeters per second on average during each stride (beak touchdown to beak touchdown).

A rosy-faced lovebird (Agapornis roseicollis) moves across an experimental setup meant to study beakiation. The bird stretches its neck and grabs onto a thin bar, releases the bar from its feet, swings its body to the side and then grasps the bar again with its feet in a new location.

“This wasn’t something that the parrots were trained to do,” says NYIT biomechanist Edwin Dickinson. “This was an innovative solution to a novel problem.” Parrots are known to be brainiacs, after all (SN: 1/26/24).

The bar was segmented into three pieces, with the central bar hung from an instrument that measures force. Using those readings and other measurements across 129 strides, the researchers calculated beakiation’s energy efficiency. The birds lost most of the energy they put into a swing: The exchange of potential and kinetic energy during the slow but pendulumlike movement recovered, on average, about 24 percent of the energy expended.

For comparison, gibbons (Hylobatidae) recover nearly 80 percent of the energy put into a stride when they swing between branches using their arms. This movement, called brachiation, is fast and smooth. Beakiation, on the other hand, consists of careful movements that start and stop.

“I see this as one of many different beak-assisted gaits that parrots use,” says biomechanist David Lee of the University of Nevada, Las Vegas, who was not involved in the study. The birds typically live in dense forests where flying can be difficult, so sometimes vines and fine branches provide the only paths, he says. “They’re navigating complex 3-D environments all the time.”