North Atlantic seabirds face high-intensity cyclones each year on their migration routes, adverse conditions that, coupled with the fact that some species are not adapted to flying with strong winds, cause many specimens to end up. starving.
A team of researchers followed more than 1,500 bird specimens, such as Antarctic frigatebirds, Atlantic divers, three-toed gulls and two types of algae, which they equipped with small beacons.
These are some of the seabirds of which thousands of very thin carcasses are found every winter on the coasts of Europe and North America.
The study published by Current Biology indicates that the cause of these deaths are high-intensity cyclones that can last for days and must be faced during migration from their nesting sites in the Arctic to the United States. ‘North Atlantic, further south, where they overwinter in more favorable conditions.
The beacons allowed the team to compare the movements of birds with the trajectories of cyclones, to determine their degree of exposure to meteorological phenomena.
Scientists created a model to calculate the energy expenditure of birds and the study suggests that birds do not die from an increase in it, but from their inability to feed during a cyclone.
The species studied are especially ill-adapted to fly when there are strong winds and some cannot dive into a stormy sea which prevents them from feeding, says the National Center for Scientific Research (CNRS) in France, which participated in the study.
Animals will starve to death if they have to deal with a cyclone that lasts beyond the few days that their body reserves allow them to resist without feeding.
The frequency of high-intensity cyclones in the North Atlantic is increasing with climate change, so animals wintering in this area will be increasingly vulnerable to them.