Meet the Museum Scientist Studying Modern Birds and Fossils to Understand How Ancient Avians Took Flight

Smithsonian researcher Klara Widrig studies living birds to build 3D models of their ancestors’ anatomies, uncovering how flight evolved

It’s not easy to fly. Bird flight is a complex and energy-intensive activity, and flight muscles can take up almost a quarter of a bird’s body mass. But flying also gives birds advantages over earthbound creatures: they can take flight to escape from predators, migrate to regions with better conditions and scan the landscape from above with a literal bird’s-eye view. Powered flight like that of birds is evolutionarily rare, having only evolved independently three times in vertebrate animals. So how did birds develop this incredible ability?

Today’s birds are descended from dinosaurs; specifically, a group of carnivorous dinosaurs called theropods. Strong anatomical similarities between modern-day birds and theropod fossils show that the birds singing outside your window are actually living dinosaurs. But there are still gaps in our understanding of how exactly birds first evolved, including when and how they first began to fly.

Klara Widrig, a postdoctoral research fellow at the National Museum of Natural History, is on the case to determine when this fateful first flight occurred. She previously studied how modern flightless birds, like ostriches and cassowaries, evolved from flying ancestors that lived millions of years ago. Now she’s turning the clock back even further to explore the origin of bird flight itself. By studying early bird fossils and compiling data on the muscles of living bird species, she is reconstructing the musculoskeletal systems of extinct birds via 3D models to understand how they moved and flew. She hopes to determine which flight muscles were present in the common ancestor of all living birds.

What inspired you to study the evolution of flight?

I’ve wanted to be a paleontologist since I was about four, and I just didn’t change my mind. I was always that kid that was really interested in dinosaurs. The more I learned, the cooler I found it that birds are just dinosaurs that are still with us today. I wondered, what’s so special about birds that they survived when the rest of the dinosaurs didn’t? And how did they evolve the unique trait of flight?

As an undergraduate, I learned that birds are one of the only vertebrates that developed flight. It’s just birds, bats and pterosaurs [an extinct group of flying reptiles that lived alongside dinosaurs]. That made me wonder if there’s something special about a particular group that predisposes it to evolving flight. All of these questions got me really interested in bird flight evolution, and I got to study bird wing musculature for the first time during my master’s program.

Since muscles aren’t preserved in fossils, how do you study the musculature of extinct birds?

Muscles are soft tissue and they rot away. So, we have to study the muscles in living animals to get a sense for the kinds of marks that different muscle attachments leave on bones. We can then look at the marks on fossil bones and determine which muscles they correspond to in the living animals. We use those clues to piece together what these ancient muscles might have looked like, because we don’t actually have the muscles anymore.

I’ve gathered all the muscle origin and attachment sites for about 25 bird species from the literature, along with those markings that muscles leave on the bone. So now I’m using the data from living birds to figure out which flight muscles might have been present in the common ancestor of all living birds. I’m starting with more modern fossil birds, and then hopefully we can work even further back. I’m currently looking at two ancient birds, Lithornis and Ichthyornis, and trying to reconstruct those two animals based on my modern bird data.

How hands-on do you get with modern bird specimens?

I recently wrapped up a project where I stained and scanned the Southern Screamer (Chauna torquata) which is a giant South American bird the size of a Canada Goose with claws on its wings. I’m looking forward to that paper coming out because it will be one of the first published descriptions of any bird wing in that general group of birds.

Scanning the bird was a challenge. It was stored in liquid, and we had to get it out of its bucket and seal it in plastic bags so it wouldn’t drip all over the scanner. The feathers hold so much water that we were squeegeeing them dry. We had to be creative and stuff the bird into a big bucket, and even then, the spurs on its wings would poke holes in the plastic bags, so we had to bandage them. Even in death, the bird was still fighting.

Looking forward, what excites you the most about your research?

I’m hoping that this work will be valuable not only for understanding how birds fly, but for advancing modeling techniques in general for other scientists and engineers. Even if they have different goals, maybe they can look at this work and find pieces of it that help them.

"I was always that kid that was really interested in dinosaurs. The more I learned, the cooler I found it that birds are just dinosaurs that are still with us today."
— Klara Widrig, Postdoctoral Researcher at NMNH

My dream is to one day build a model of Archaeopteryx — one of the oldest representatives of the bird lineage — and see how it may have moved. It’s a really famous fossil that’s been known since Darwin’s time as an amazing missing link that shows us how birds evolved. It’s a fossil that really captures the imagination that way.

How does your work today measure up to your childhood dreams of being a paleontologist?

When you’re a kid, you think that paleontology is all digging holes in the ground. And I still really like digging holes in the ground and digging up bones. I hope I have more chances to get back out in the field and do collecting in the future.

But I’m really glad that all of the modeling I do allows me to apply my artistic skills. This might surprise people because we often say that science is all math, and if you want to be a scientist, you need to be really good at math — but I would say, if you want to be a scientist, you should try to be as good as you can in all your subjects. You can apply pretty much any skill to becoming a stronger scientist.

Meet a SI-entist: The National Museum of Natural History is so much more than its famed exhibits and world-renowned collection of specimens and objects. It is a hub of scientific exploration for hundreds of researchers from around the world. Once a month, we’ll introduce you to a Smithsonian Institution scientist (or SI-entist) and the fascinating work they do behind the scenes at the National Museum of Natural History.

Ashley D'Souza | Read More

Ashley D’Souza is a science writing intern at the Smithsonian’s National Museum of Natural History, where they cover natural history research and collections news for the museum’s blog, Smithsonian Voices. Ashley is currently completing their master’s degree in science writing at MIT, where they write about any and all things wildlife. They also run the blog and YouTube channel, Confessions of a Bird Freak. In their free time, Ashley can be found wandering through the woods with their camera and binoculars and talking to trees and birds. See more of Ashley’s work at https://ashleydsouza.contently.com/ and https://confessionsofabirdfreak.com/.