details of behaviour classification methods from Migrating ospreys use thermal uplift over the open sea.

• Main Authors: Olivier Duriez, Guillaume PERON, David Gremillet, Andrea Sforzi, Flavio Monti
• Format: Other Non-Article Part of Journal/Newspaper
• Language: unknown
• Published: 2018
• Subjects: Ecology; Animal Behaviour; Pandion haliaetus; raptor; Mediterranean Sea; migration; soaring-gliding flight; ecological barrier; osprey
• Online Access: https://doi.org/10.6084/m9.figshare.7403918.v2; https://figshare.com/articles/journal_contribution/details_of_behaviour_classification_methods_from_Migrating_ospreys_use_thermal_uplift_over_the_open_sea/7403918

Most large raptors on migration avoid crossing the sea because of the lack of atmospheric convection over temperate seas. The osprey Pandion haliaetus is an exception among raptors, since it can fly over several hundred kilometres of open water. We equipped five juvenile ospreys with GPS-Accelerometer-Magnetometer loggers. All birds were able to find and use thermal uplift while crossing the Mediterranean Sea, on average 7.5 times per 100 km, and could reach altitudes of 900 m above the sea surface. Their climb rate was 1.6 times slower than over land, and birds kept flapping most of the time while circling in the thermals, indicating that convections cells were weaker than over land. The frequency of thermal soaring was correlated with the difference between the sea surface and air temperature, indicating that atmospheric convection occurred when surface waters were warmer than the overlaying air. These observations help explain the transoceanic cosmopolitan distribution of osprey, and question the widely held assumption that water bodies represent strict barriers for large raptors.