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Rosy-faced lovebirds are small, charismatic parrots. They are also not afraid to use their heads, literally, to get around an uncomfortable situation.
“They’re these incredibly intelligent animals that are really good at problem solving, and that also extends to the way they move,” said Edwin Dickinson, a biomechanist at the New York Institute of Technology.
The parrots recently demonstrated their talents to Dr. Dickinson and his colleagues in a laboratory as they navigated increasingly smaller perches. When a rod became thin enough, the birds stopped trying to balance on two legs. Instead, they moved under the wire, hanging from their beaks and swinging their legs and bodies, almost like a monkey swinging from tree to tree in a forest. While parrot owners may have detected such beak movement in their pets, scientists set out to understand the forces behind it, which described Wednesday in the journal Royal Society Open Science.
It is not the first time that parrots have been observed using their heads to survive. In a previous study, the same team gave lovebirds a walking surface, making it progressively steeper. As the angle of the track increased, the birds began to use their beaks to grab hold and help them climb. Researchers have even gone so far as to suggest that the animals essentially walk with three limbs.
For their latest study, the team placed a sensor that measured forces in the birds’ path and observed that the head does more than stabilize movement when the birds move their legs along the wire.
“In the sense of limb loading, they are able (in the head itself) to support the entire weight of the body with just the head, which is quite remarkable,” said Melody Young, a biomechanist at the New York Institute of Technology. and author of the study.
The move is “quite unusual,” said Pauline Provini, an evolutionary biologist at the National Museum of Natural History in Paris. A bird uses its beak for feeding and also plays a role in calls and songs. “But for locomotion, it’s relatively rare,” she said.
The movement pattern involved in using the head as a third limb requires parrots to coordinate their beaks and legs. “We tend to see birds simply as wings because flight is wonderful,” Dr. Provini said. But birds have developed various ways of using their legs: walking, jumping, paddling and perching. And their heads and necks are very powerful, he noted.
The movement of the beak resembles the movement of monkeys. So scientists coined the term “beakiation,” a play on the word brachiation, the term for primate barbell movements. The researchers compared the beak motion of parrots to the brachiation of gibbons (whose movements bounce with momentum) and the inverted walking of sloths. The team discovered that the parrots’ swings meet in the middle. Like gibbons, spider monkeys, and humans with their arms, birds can hang their entire weight from their beak, which acts as a limb. But they don’t recover as much energy as primates do on their swings.
It’s unclear how common beaking is in wild birds, but researchers hope that scientists in the field will be able to observe beak movement. “It is likely that parrots around the world have been doing or are capable of doing something similar since time immemorial,” Dr Dickinson said.
Other birds can use beak movement, said Diego Sustaita, an organismal biologist at California State University, San Marcos, who was not involved in the work. For example, beyond parrots, researchers may want to look at other tree-climbing inhabitants, such as mousebirds or trogons. Comparison between species could provide clues about the evolution of behavior.
The new research also contains a note of caution for scientists who might make assumptions about how extinct animals moved by studying their anatomy, said Michael Granatosky, whose lab at the New York Institute of Technology has been examining the movements of parrots. .
Biologists often assume that form predicts function. But the swaying of the beak shows that sometimes animal anatomy works in ways that scientists wouldn’t predict from its shape. People do not usually consider moving with their neck or mouth, but rather use systems that primarily control feeding. But scientists constantly gain clues about the movements of ancient creatures from their fossils.
“If we try to predict what they did just from their bones, we’re probably missing entirely new forms of locomotion or things that animals could have done that we would never have imagined,” Dr. Granatosky said.