Body measurements of 11,000 bird species published in open-access database


The database contains measurements of nine body characteristics, or traits. Credit: Imperial College London

A new database called AVONET contains measurements of more than 90,000 individual birds, allowing researchers to test theories and help with conservation.

AVONET was put together by a team of international researchers, led by Dr Joseph Tobias, from the Department of Life Sciences at Silwood Park at Imperial College London. In a special issue of the journal Ecology Lettersedited by Dr. Tobias, he and researchers around the world present the first iteration of the full AVONET database and some early results using the data.

Hayley Dunning explained to Dr. Tobias why such a database is needed, how it came about, and what she has already discovered about the evolution and ecology of birds around the world.

What bird traits are recorded in AVONET, and why are they important to study?

For each individual bird, we measured nine “morphological” traits, related to the physical aspects of their body: four beak measurements, three wing measurements, tail length, and tarsus (lower leg) length. AVONET also includes body mass and the hand-wing index, which is calculated from three wing measurements to give an estimate of flight efficiency, and therefore a species‘ ability to disperse or move through the landscape.

The final version contains measurements of 90,020 individual birds at an average of about nine individuals per species.

These measurements have been shown to correlate with important ecological characteristics of species, including what they eat and how they forage for food. Previous studies have most often used fairly broad categories, such as habitat, life history, or major food type, but these can be coarse and relatively consistent across species. Some studies have included estimates of body size, but it is clear that the link between body size and ecological function is relatively weak – for example, hawks and ducks have similar body masses, but that says very little. on their role in the ecosystem.

Measurements of the beak, wings and legs provide much richer information, for example on the place of the species in the local food web, its movements and the distance traveled. Combinations of these traits can predict key functional characteristics of bird species, such as their precise diet and foraging behavior, with much greater accuracy than body mass alone.

How was the project born?

To a certain extent, the publication of AVONET marks the end point of a personal journey. My own fascination with the characteristics of birds began in the 1980s as a schoolboy traveling the tide lines and power lines of Northumberland looking for dead birds to dismember. I owe a belated debt of thanks to my mother for respecting the bedroom shelves full of skulls and the cabinets laden with smelly wings and tarsi.

General interest in studying the morphological traits of birds to predict ecology dates back to the 1960s, but it was not until the 2000s that major studies accelerated the trend. Over the past two decades, several research groups have compiled and analyzed bird trait datasets of progressively increasing size, initially targeting samples of a few hundred species, and more recently covering thousands of species. in the world.

However, these resources have until now been fragmented, with largely incompatible and unpublished raw data. The AVONET project represents an international collaboration between this network of avian researchers aimed at making their data accessible to the next generation of researchers. The company’s initial inspiration was the TRY database of plant characteristics, a successful catalyst for high-impact research in ecology and ecosystem science over the past decade.

Body measurements of 11,000 bird species published in open-access database

Before and after: Dr. Joe Tobias at the start of data collection (with Ondulated Antpitta, Ecuador, 1991) and after finalizing the AVONET dataset (with Blue-moustached Bee-eater, Ghana, 2021). Credit: Imperial College London

How was the data collected?

AVONET is the result of managers of different bird trait datasets joining forces to merge their work. The completion of this first iteration – AVONET 1.0 – is a truly international effort, with expertise and vital data provided by 115 authors based in 106 institutions in 30 countries.

Most measurements were taken from museum specimens, particularly the Natural History Museum in London and the American Museum of Natural History in New York, with smaller specimens from 76 other collections.

In fact, the history and care of these specimens means that the project relies on the contributions of countless museum curators, field assistants and specimen collectors since the mid-1800s, including some luminaries, including Charles Darwin , Alfred Russell Wallace, Ernest Shackleton, and John James Audubon, all of whom prepared subsequently measured specimens for trait data.

What kinds of insights has AVONET data already provided and what future questions might it answer?

The data has been a great tool for testing the “rules” of evolution – patterns of evolution that seem prevalent, but remain controversial for one reason or another. For example, we used it to test the “island rule”, where animals living on islands tend to evolve into giants or dwarfs compared to their mainland ancestors. We found that this particular “rule” explains how the bodily evolution of animals varies across Earth’s islands, with an effect partly controlled by island size and isolation. There are many other such rules that could be studied.

A hand-wing index study also showed how dispersal ability varies across all bird species, providing insight into a range of topics such as their sensitivity to habitat loss or their ability to track appropriate climates under climate change.

More generally, AVONET data can help us understand and predict how ecosystems respond to environmental change. For example, some early studies have looked at how the world’s bird communities differ in their functional diversity – the shape and variety of species fulfilling useful roles. These estimates can provide information on the state of useful ecological processes, such as seed dispersal and pest control, and their resilience to changing habitats and climates.

What future for AVONET?

Progress is underway towards AVONET 2.0, which will be expanded with more measurement data for each species, as well as more information on life history and behavior. Meanwhile, we hope that AVONET 1.0 can provide a rich resource for teaching and research in a wide range of life science fields.

In particular, we hope to use data on bird characteristics to develop an index of ecological health that can be used to identify and track progress towards effective conservation actions designed to preserve biodiversity and ecosystem functions worldwide. .

The shape of the wings determines the dispersal distance of the birds

More information:
Joseph A. Tobias et al, AVONET: morphological, ecological and geographical data for all birds, Ecology Letters (2022). DOI: 10.1111/ele.13898

Joseph A. Tobias, A Bird in the Hand: Global-scale Morphological Trait Datasets Open New Frontiers of Ecology, Evolution, and Ecosystem Science, Ecology Letters (2022). DOI: 10.1111/ele.13960

Provided by Imperial College London

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