bye bye birdie

Look: Why birds in the Amazon rainforest are changing

Even the most geographically remote species can't avoid the climate crisis.

by Jennifer Walter
Updated: 
Originally Published: 
Vitek Jirinec

Vitek Jirinec

Some animals are adapting to the climate crisis in a very visible way: they’re altering the shape of their bodies.

Giorgio Roncaglia / 500px/500px Prime/Getty Images

Bigger ears, longer tails, and lengthier legs can make it easier for different species to regulate their body temperatures when the heat spikes.

Even the most remote animals are undergoing pressure to change due to the climate crisis.

A study published November 12 in the journal Science Advances documents the altered bodies of birds living in the Amazon rainforest over the course of 40 years.

Vitek Jirinec

Planet Observer/Universal Images Group/Getty Images

The Amazon has become significantly hotter and drier. These changes are largely attributed to human activity.

Cameron Rutt

The study’s data suggests — in an effort to survive — the wingspans of birds are collectively getting longer, while their bodies are getting smaller.

Vitek Jirinec

When a bird’s body is smaller, it doesn’t require as much energy to lift itself off the ground.

That also means it won’t generate as much metabolic heat.

Many birds living in the Amazon are non-migratory species.

That means researchers have a better idea of what bodily effects are caused by climate change, minimizing the presence of factors that may tie in with migratory behaviors.

Cameron Rutt

Vitek Jirinec

Since 1980, this study team has captured and released birds from 77 species living in remote areas of the Amazon.

Over the course of 40 years, more than 15,000 individual birds were assessed.

The shrinkage is happening to birds at every level of the forest. On average, birds lost 2 percent of their body weight each decade.

Jirinec et. al./Science Advances

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“These birds don’t vary that much in size. They are fairly fine-tuned, so when everyone in the population is a couple of grams smaller, it’s significant.”

Philip Stouffer, study co-author

How Amazonian birds will fare in the coming decades remains an open question, especially if the climate crisis becomes even more severe.

Vitek Jirinec

Shrinking birds have been observed elsewhere, too.

The researchers say that further analysis may uncover similar trends across the globe.

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