All birds, one tree: Complete evolutionary map reveals hidden links

A groundbreaking new study has produced the most complete evolutionary tree of birds ever assembled.

The researchers combined decades of genetic and ecological data to trace how every known bird species is connected, creating a powerful resource for understanding the history of bird evolution and offering a foundation for future research.

The study was led by Professor Emily Jane McTavish and her team at the Cornell Lab of Ornithology. They worked to gather and organize data on 9,239 bird species, pulling from nearly 300 published studies released between 1990 and 2024.

An evolutionary map for birds

In addition to this, the data covered another 1,000 species, bringing together a vast pool of information. This effort resulted in a single, unified evolutionary tree that can easily be updated and shared as more studies are published in the future.

“People love birds, and a lot of people work on birds. People publish scientific papers about birds’ evolutionary relationships all the time,” McTavish said. “We synthesized all the data to have unified information all in one place.”

The team noted that this synthesis tree has the potential to support a wide range of research projects. It can help scientists explore key questions about bird evolution, biodiversity, and ecology.

Even more importantly, the same methods used to construct this tree could be applied to other groups of animals and plants, making it a valuable tool far beyond ornithology.

A bird evolutionary tree is formed

The idea for this massive undertaking first took shape about four years ago. Eliot Miller, who was then working at the Cornell Lab, reached out to McTavish with the proposal. At the time, McTavish had already been involved for nearly a decade with software development for the Open Tree of Life (OpenTree) project, which is designed to map how all living species are related.

“Many dozens of bird phylogenies (studies of evolutionary histories using genetics) get published every year, yet their findings – with implications for everything from taxonomy to our understanding of ancestral characters – aren’t necessarily being used for downstream research,” Miller said.

“Our project should help to close this research loop so that these studies and their findings are better incorporated into follow-up research.”

McTavish noted that even though she and Miller had not worked together before, the collaboration felt natural and productive.

“Eliot is really into birds, and the lab is full of bird experts, and they also develop birding apps such as Merlin and Ebird, so that was their side of it,” said McTavish. “And I’ve been working on this software to combine evolutionary trees, so that was my side of it.”

Linking all species on Earth

The OpenTree project is a large-scale collaboration between evolutionary biologists and taxonomy specialists who aim to construct an accurate and comprehensive evolutionary tree. This tree seeks to describe how every named species on Earth is related to all others.

The platform functions like a wiki, where users can upload data manually to update relationships between species.

McTavish explained that as new studies and data reshape our understanding of how species are connected, users can add this updated information to the Tree of Life. This process ensures that the tree remains as current as possible, reflecting the latest scientific insights.

Today, the Open Tree of Life includes over 2.5 million species, and its coverage is continually expanding. Advances in genome sequencing have provided a flood of new data, helping to fill in the many gaps that remain in our understanding of life’s evolutionary history.

McTavish, who works as a biologist in the Department of Life and Environmental Sciences at the School of Natural Sciences, has been developing software that can automatically integrate this steady flow of data into the OpenTree. The recent synthesis of bird species adds another critical piece to the global puzzle.

Looking ahead to future discoveries

The creation of this comprehensive bird evolutionary tree is more than just an academic exercise. It provides a practical, accessible framework that other scientists can use to answer new questions.

By offering a clear picture of how bird species are related, researchers can better explore patterns of adaptation, speciation, and ecological interaction across the avian world. Moreover, the methods developed through this work are not limited to birds.

They can be applied to a wide range of other life forms, helping scientists to construct equally detailed evolutionary maps for plants, mammals, insects, reptiles, and more. This opens the door to broad, cross-species research that could reveal large-scale patterns and processes shaping life on Earth.

By building tools that automatically update as new data emerges, the OpenTree project also ensures that researchers can work with the most current knowledge available. This dynamic, living map of life’s connections has the potential to reshape not only how we understand evolution, but also how we study the world’s biodiversity.

The study is published in the journal Proceedings of the National Academy of Sciences.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–