title: Frigate birds track atmospheric conditions over months-long transoceanic flights.
abstract: Understanding how animals respond to atmospheric conditions across space is critical for understanding the evolution of flight strategies and long-distance migrations. We studied the three-dimensional movements and energetics of great frigate birds (Fregata minor) and showed that they can stay aloft for months during transoceanic flights. To do this, birds track the edge of the doldrums to take advantage of favorable winds and strong convection. Locally, they use a roller-coaster flight, relying on thermals and wind to soar within a 50- to 600-meter altitude band under cumulus clouds and then glide over kilometers at low energy costs. To deal with the local scarcity of clouds and gain longer gliding distances, birds regularly soar inside cumulus clouds to use their strong updraft, and they can reach altitudes of 4000 meters, where freezing conditions occur.
authors.affiliation: Centre d'Etudes Biologiques de Chizé, CNRS, 79360 Villiers en Bois, France. UMR 9220 ENTROPIE, Université de la Réunion, Saint Denis, La Réunion. henriw@cebc.cnrs.fr.
authors.forename: Henri
authors.initials: H
authors.lastname: Weimerskirch
authors.affiliation: School of Biological Sciences, Bangor University, Bangor, Gwynedd, UK.
authors.forename: Charles
authors.initials: C
authors.lastname: Bishop
authors.affiliation: Department of Zoology, University of British Columbia, Vancouver, Canada.
authors.forename: Tiphaine
authors.initials: T
authors.lastname: Jeanniard-du-Dot
authors.affiliation: Centre d'Etudes Biologiques de Chizé, CNRS, 79360 Villiers en Bois, France. UMR 9220 ENTROPIE, Université de la Réunion, Saint Denis, La Réunion.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Prudor
authors.affiliation: Institute of Flight System Dynamics, Technische Universität München, Garching, Germany.
authors.forename: Gottfried
authors.initials: G
authors.lastname: Sachs
mesh_terms: D000531:Altitude; D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D001717:Birds / Q000502:physiology*; D002980:Climate; D018481:Convection; D005260:Female; D005426:Flight, Animal; D005615:Freezing; D006339:Heart Rate; D008297:Male; D014919:Wind