Juvenile Osprey Navigation during Trans-Oceanic Migration

• Published in: PloS one Vol. 9; no. 12; p. e114557
• Main Authors: Horton, Travis W, Bierregaard, Richard O, Zawar-Reza, Peyman, Holdaway, Richard N, Sagar, Paul
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 10.12.2014; Public Library of Science (PLoS)
• Subjects: Analysis; Animal migration; Animal Migration - physiology; Animals; Behavior; Biology and Life Sciences; Bird migration; Birds; Caretta caretta; Drift; Earth Sciences; Ecology and Environmental Sciences; Falconiformes - physiology; Geographic Information Systems; Geomagnetic field; Global positioning systems; GPS; Hatching; Insects; Magnetic Fields; Meteorological data; Navigation behavior; Oceans; Orientation; Orientation - physiology; Physical Sciences; Reptiles & amphibians; Research and Analysis Methods; Satellite monitoring; Satellite navigation systems; Satellite tracking; Satellites; Spatial Navigation - physiology; Spatial reference frames; Thunnus thynnus; Wind; Wind effects; New Zealand; United States > US; Atlantic Ocean
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0114557

To compensate for drift, an animal migrating through air or sea must be able to navigate. Although some species of bird, fish, insect, mammal, and reptile are capable of drift compensation, our understanding of the spatial reference frame, and associated coordinate space, in which these navigational behaviors occur remains limited. Using high resolution satellite-monitored GPS track data, we show that juvenile ospreys (Pandion haliaetus) are capable of non-stop constant course movements over open ocean spanning distances in excess of 1500 km despite the perturbing effects of winds and the lack of obvious landmarks. These results are best explained by extreme navigational precision in an exogenous spatio-temporal reference frame, such as positional orientation relative to Earth's magnetic field and pacing relative to an exogenous mechanism of keeping time. Given the age (<1 year-old) of these birds and knowledge of their hatching site locations, we were able to transform Enhanced Magnetic Model coordinate locations such that the origin of the magnetic coordinate space corresponded with each bird's nest. Our analyses show that trans-oceanic juvenile osprey movements are consistent with bicoordinate positional orientation in transformed magnetic coordinate or geographic space. Through integration of movement and meteorological data, we propose a new theoretical framework, chord and clock navigation, capable of explaining the precise spatial orientation and temporal pacing performed by juvenile ospreys during their long-distance migrations over open ocean.