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Claws and Effect: Birds talented with their claws share a common ancient ancestor | CBC News

From parrots to birds of prey, birds that demonstrate dexterity with their claws share a common ancestor, new research shows.

A University of Alberta study published Aug. 15 in the Journal communication biologyexamines the development of the bird's body – namely its feet.

Researchers trying to better understand how these birds' brains differ from those of their less dexterous counterparts turned bird-loving amateur photographers into citizen scientists.

Using thousands of images shared online by bird watchers, the researchers examined how some birds became more skilled with their claws – and how the world's first birds gave rise to the diversity of bird species we know today.

Cristian Gutiérrez-Ibáñez, a neurobiologist at the U of A and the study's lead author, said that as birds developed wings, those limbs were no longer useful for eating, climbing, or nursing their young.

The researchers wanted to find out why some species developed better claws.

“Birds use their beaks to manipulate objects,” Gutiérrez-Ibáñez said in an interview. “But it's hard to open a jar with one hand, isn't it?

“The same goes for cracking a nut or eating mice. And so they started using the only thing they had left, which was their feet.”

“We wanted to understand what drives this development.”

Studying more than 1,000 species found that all birds that use their feet for tasks other than perching are part of a group of large-brained birds known as heartland birds or Telluraves. A clade is a large group of species that all trace back to a common ancestor.

An ancient ancestor

The results suggest that birds made better use of their feet and not just their beaks as they became accustomed to grasping branches in the forest canopy.

It all started 60 million years ago when the group's common ancestor, likely a predator, migrated from the forest floor to the trees.

Just like modern tree-dwelling birds, the early risers Telluraves Clade had long toes on the back that almost worked like a thumb to clasp. They also had toe tendons that gave them a better grip on perches.

The study found that the family tree kept diverging over the generations as the birds adapted to their diet or environment. The study found that adaptations occurred at least 20 times as birds further specialized their footwork for tasks like cracking nuts or clawing at prey.

The study arose out of unexpected circumstances.

It all started with owl brains.

Gutiérrez-Ibáñez and his team planned a laboratory study in Brazil to study the neural pathways of owls. But when the pandemic put those plans — and the brain samples — on hold, the team devised a new plan.

Researchers began trawling millions of bird photos and videos online, including the Macaulay Library's online scholarly archive, the world's largest archive of bird photos, and eventually selected 3,725 images for further study.

The study is a unique opportunity, thanks largely to the fact that people love to photograph birds, Gutiérrez-Ibáñez said.

“Suddenly I realized that there are a lot of pictures and videos of birds on the internet and this particular behavior lends itself very well to that because the birds do it when they are sitting still.”

“It's a behavior that you can even study from a picture.”

A black and white bird with a blue stripe on the wing stands in light brown soil.
Using thousands of images taken by birders, the researchers looked at how some birds became more talented with their claws. The study found that magpies were among the most agile animals. (Kathryn Keith)

The study found that there was a variety of skills. Parrots were the most skilled of all. They can grab, twist their claws and bring their feet up to the beak. Next up would be birds of prey like owls and vultures.

However, some corvids like magpies are only capable of holding an object against a branch. Most songbird species have limited or no grasping ability.

It is unclear exactly why each adjustment was made. According to Gutiérrez-Ibáñez, various evolutionary constraints likely played a role, including changes in habitat and diet.

He said the issue of the birds' dexterity is a largely ignored behavior. But ultimately, a better understanding of birds' feet could help scientists better understand bird brain development.

“From other research, we know that these central landbirds have large brains, and we think they may also have differential connections, similar to mammals where there are direct connections to the motor centers that control limb movement,” he said .

“It's very likely that these birds have evolved something to control this behavior that other birds don't have.”

Peter Arcese, a professor of conservation science at the University of British Columbia, said the study is a clever approach to community-based science that has enabled researchers to provide comprehensive insights in a relatively short period of time.

Arcese was not involved in the study. He hopes the project will show that citizen scientists can be important actors in the research field.

“It's really important that the so-called average person out there realizes how much they can contribute,” he said.

“It shows how important it is to think outside the box.”

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