Secrets of how birds soar is revealed: Spirals of wind help creatures catch thermals

Migratory birds use warm, rising currents of air to gain height using little energy to fly over long distances. But just how they navigate the height-boosting currents was a mystery, until now. Now, biologists have used mathematical models to demonstrate birds use'torque and vertical wind' to help them pick the most efficient soaring path through thermals. High fliers: Biologists have used mathematical models to demonstrate birds such as eagles (stock image) use'torque and vertical wind' to help them pick the most efficient soaring path through thermals Most migrating birds fly between 656 and 3,937 feet (200 to 1,200 metres) above sea level. When the wind s against them, they stay closer to Earth when obstacles like trees slow the wind down.