Plovers were killed by peregrine falcons at an altitude of 3,000 m

In January 2023, scientists attached tracking devices to eight gray plovers in the Wadden Sea coastal region of the Netherlands. They hope to learn more about the birds’ annual migration to their Arctic breeding grounds. Everything went smoothly until late May, when one of the birds started acting strangely.

First, Michiel Boom, a migration ecologist at the University of Amsterdam, and his colleagues noticed the sudden change in direction. While the rest of the plovers headed northwest, this bird flew southeast. In fact, it appeared to descend rapidly before landing in a quarry. a very unusual destination for the gray plover. Not long after, the bird’s tracking device stopped working. Obviously, the bird was not confused about the direction, it fell into the clutches of the bird of prey.

But a closer look at the data reveals something curious. Regardless of what happened to the plover, the tracker’s GPS signal showed it happened at an altitude of more than 8,000 feet. From sea level, that’s much higher than birds of prey normally operate.

Other evidence points to this being a high-altitude hunting display. For example, the data revealed that plovers accelerated briefly before changing direction. Most likely it saw the attacker and tried to escape but failed. In addition, when collecting plovers and tracking rings in Sweden, scientists discovered a large kestrel nest 198 m away.

In research published in the journal Ecology, Boom and his colleagues provide evidence of the highest predation ever recorded. He emphasized that hunting activity takes place all the time on mountain slopes or plateaus. But the struggle for survival at an altitude of nearly 3,000 m is very rare. This accident may help explain why migrating birds fly so high.

For example, long-billed wading birds like the great snipe fly at altitudes of more than 7,000 m. Similarly, the great reedbird flies 2,377 m above sea level at night but climbs as high as 6,096 m during the day. They can find ways to avoid predators.

Two factors may make flying worthwhile for peregrine falcons. There are large flocks of migratory birds that fly really high, so it is to their advantage to hunt high up. When catching prey at such a high altitude, birds of prey can save energy by flying in slow circles to a safe location.

They’re Khang (Theo IFL Science)