Seasonal migrations are a dangerous period in the life of a migratory bird. Threats include attacks from predators, which biologists say forces the birds to maintain altitude many kilometers away. But the authors of the new paper showed that such a strategy does not always work. With the help of a GPS tracker attached to the leg of the Tules Pluvialis squatarola, they were able to reconstruct the last minutes of its life and obtain information about the circumstances of the bird’s death.

Many birds make seasonal migrations, and the length of such routes is sometimes very long. For example, Arctic tern Sterna paradise It is constantly moving from the Arctic to Antarctica and back, covering a distance of more than 70 thousand kilometers per year. Landmarks for birds are the position of the stars and the Earth’s magnetic field.

Despite the obvious benefits of access to the best feeding and nesting areas, long-distance migrations come with many risks. Birds may be exposed to adverse weather conditions or fall victim to predators. Ornithologists have previously suggested that danger drives feathered travelers to higher altitudes where they are less likely to be attacked.

Authors of a new article in the journal Ecology I decided to tell about Tules migrations. Pluvialis squatarola . It is a medium-sized bird from the plover family that lives near the seashore and feeds mostly on invertebrates. Tules nest in the Arctic tundra and overwinter in warm places: Africa, South Asia, Australia and the New World.

four people P. squatarola It was captured in January 2024 off the coast of the Wadden Sea in the Netherlands. A small device with GPS and an accelerometer (weighing less than eight grams) was attached to each leg, which constantly sent data about its coordinates and acceleration of movement. The lighthouse used solar energy for power and 2G network for information transmission. The released birds followed the standard route across the Baltic Sea to the Russian Arctic. But only three tul reached near Lake Onega and the White Sea.

The fourth was unlucky: he disappeared “off the radar” over Swedish territory. With the help of tracker data and support from local colleagues, scientists were able to understand exactly what was happening to the bird.

On May twenty-seven, at 21.58 local time (25 minutes after sunset), after 15 minutes of very intense flight, the tuller suddenly stopped. Its momentum dropped several times and within two minutes it stopped at 2882 meters above sea level. The tracker’s movement changed direction dramatically (from northeast to southwest) and its average speed now equaled approximately six meters per second instead of the usual 14 meters per second. Tules’ coordinates stopped changing at midnight; stopped eight kilometers from the scene.

Using the tracker’s signal, Swedish ornithologists managed to find the device, and with it the remains of the bird. It was less than 200 meters from the peregrine falcon’s nest Falco peregrinusA predatory animal from the hawk family. The peregrine falcon is known for its record-breaking flight speed (up to 90 meters per second), the ability to fly at altitudes of more than five kilometers, and for attacking migratory birds.

The result is obvious: the hunter caught the migrating tulips, which tried to escape for a long time, at an altitude of almost three kilometers. This means that even this far from the ground, migratory birds are not protected from attack, and the Swedish peregrine falcon broke the hunting height record.