Flying might seem like one of the most energy-demanding ways for animals to travel. Yet a groundbreaking international study suggests that certain birds can move through the air more efficiently than animals swimming through water.

Researchers from the Max Planck Institute of Animal Behavior and Swansea University discovered that atmospheric conditions dramatically influence the energy required for flight.

Published in the journal Science in October 2026, the findings challenge traditional assumptions about animal movement and reveal how birds take advantage of natural forces to conserve energy.

Why Some Birds Fly More Efficiently

Scientists have traditionally considered swimming the most energy-efficient form of animal movement, followed by flying and running. However, these comparisons were largely based on laboratory experiments that failed to account for the influence of natural air currents.

The new research demonstrates that some birds can travel extraordinary distances with remarkably little physical effort. The secret lies in soaring, a flight technique that allows birds to use rising air currents rather than constantly beating their wings. By exploiting these atmospheric conditions, certain species can maintain altitude and travel considerable distances while conserving energy.

Condors And Swans Reveal The Difference

One particularly striking comparison involved Andean condors and trumpeter swans. Both birds weigh approximately 11 kilograms, yet their energy requirements during flight differ dramatically. Researchers found that an Andean condor can travel one kilometre using just one-fifth of the energy required by a trumpeter swan. The explanation lies in their different flying techniques.

Condors rely heavily on rising air currents, spending only around 0.1% of their flight time flapping their wings. Trumpeter swans, by comparison, flap for approximately 99% of their flight time. Despite their similar body mass, the two species therefore experience very different energetic costs.

What The Research Discovered

The international team analysed 17 years of tracking information collected from 850 birds and bats representing 38 species. Researchers combined GPS measurements with accelerometer data to distinguish energy-intensive wingbeats from more economical soaring. They also examined four years of radar observations covering 12 size categories of smaller flying animals. This extensive dataset allowed scientists to compare movement efficiency across species under real environmental conditions.

Seven species of vultures collectively travelled more than 4.3 million kilometres while flapping for just 0.1% to 7% of their flight time. The findings revealed that heavier soaring birds generally relied less on active wingbeats, allowing them to travel at a lower energetic cost.

Why Efficient Flight Has Limitations

Although soaring offers substantial energy savings, it also creates challenges. Large birds that depend on favourable air currents cannot always choose when or where to travel. Their movements are influenced by wind conditions and the availability of rising air. Species that rely on continuous wingbeats consume more energy but can operate under a wider range of atmospheric conditions.

This reveals an important trade-off between conserving energy and maintaining flexibility. For soaring birds, travelling efficiently often depends on being in the right place at the right time.

What Climate Change Could Mean

The findings may also improve understanding of how changing weather patterns affect animal movement. Alterations in wind systems and rising air currents could influence the routes birds use, the distances they travel and the energy required for migration.

Researchers suggest that changes in atmospheric conditions may eventually affect where flying animals establish populations. The study highlights how closely wildlife depends on environmental forces that are often invisible from the ground. Understanding these relationships could help scientists anticipate future changes in bird migration and develop more effective conservation strategies.

The discovery offers a new perspective on flight: for some animals, the surrounding atmosphere provides an essential natural energy resource.