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Juvenile Osprey Navigation during Trans-Oceanic Migration.

Horton TW, Bierregaard RO, Zawar-Reza P, Holdaway RN, Sagar P - PLoS ONE (2014)

Bottom Line: 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.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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Geological Science, University of Canterbury, Christchurch, New Zealand.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus

Hourly-scale juvenile osprey navigational responses to wind during trans-oceanic migration.Symbols and colors as in Figure 1. Symbol size is proportional to wind velocity (A) and forward movement velocity (B) as shown in the velocity legend. Blue vectors (B) correspond with the wind direction and wind speed (scale bar shown) experienced by the juvenile osprey ‘Felix’ during his>1500 km constant course movement between Martha's Vineyard and the Bahamas between the morning of September 16 and evening of September 17, 2007.
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pone-0114557-g006: Hourly-scale juvenile osprey navigational responses to wind during trans-oceanic migration.Symbols and colors as in Figure 1. Symbol size is proportional to wind velocity (A) and forward movement velocity (B) as shown in the velocity legend. Blue vectors (B) correspond with the wind direction and wind speed (scale bar shown) experienced by the juvenile osprey ‘Felix’ during his>1500 km constant course movement between Martha's Vineyard and the Bahamas between the morning of September 16 and evening of September 17, 2007.

Mentions: These two insights into juvenile osprey migratory behavior are best demonstrated by the hourly-scale PTT tag locations and associated WRF wind vector data for individual track segments. The five longest juvenile osprey track segments we observed, all in excess of 1000 km, spanned at least 18 hours of non-stop flying over open ocean (Table 1). Hourly-scale analysis of these data reveals that each of these track segments describe remarkably constant course paths despite the presence of highly variable wind speeds and directions across the track paths (Figure 6). In order to maintain the observed constant course groundtrack directions, these birds had to change their heading directions by as much as 90° (Figure 6A). This high-resolution analysis further demonstrates that when these birds experienced stronger winds, they followed heading directions that were as much 76° oblique to their near constant groundtrack directions, and followed heading directions that were similar to their groundtrack directions when winds were lighter (Figure 6A). It is worth noting that had these birds experienced full-wind drift, and not compensated for the effects of wind displacement, our high-resolution analysis would have shown the opposite pattern to what is presented in Figure 6A. In the case of full-wind drift, the data would plot as near constant heading directions with highly variable groundtrack directions due to the extremely dynamic nature of the winds these birds flew through.


Juvenile Osprey Navigation during Trans-Oceanic Migration.

Horton TW, Bierregaard RO, Zawar-Reza P, Holdaway RN, Sagar P - PLoS ONE (2014)

Hourly-scale juvenile osprey navigational responses to wind during trans-oceanic migration.Symbols and colors as in Figure 1. Symbol size is proportional to wind velocity (A) and forward movement velocity (B) as shown in the velocity legend. Blue vectors (B) correspond with the wind direction and wind speed (scale bar shown) experienced by the juvenile osprey ‘Felix’ during his>1500 km constant course movement between Martha's Vineyard and the Bahamas between the morning of September 16 and evening of September 17, 2007.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4262435&req=5

pone-0114557-g006: Hourly-scale juvenile osprey navigational responses to wind during trans-oceanic migration.Symbols and colors as in Figure 1. Symbol size is proportional to wind velocity (A) and forward movement velocity (B) as shown in the velocity legend. Blue vectors (B) correspond with the wind direction and wind speed (scale bar shown) experienced by the juvenile osprey ‘Felix’ during his>1500 km constant course movement between Martha's Vineyard and the Bahamas between the morning of September 16 and evening of September 17, 2007.
Mentions: These two insights into juvenile osprey migratory behavior are best demonstrated by the hourly-scale PTT tag locations and associated WRF wind vector data for individual track segments. The five longest juvenile osprey track segments we observed, all in excess of 1000 km, spanned at least 18 hours of non-stop flying over open ocean (Table 1). Hourly-scale analysis of these data reveals that each of these track segments describe remarkably constant course paths despite the presence of highly variable wind speeds and directions across the track paths (Figure 6). In order to maintain the observed constant course groundtrack directions, these birds had to change their heading directions by as much as 90° (Figure 6A). This high-resolution analysis further demonstrates that when these birds experienced stronger winds, they followed heading directions that were as much 76° oblique to their near constant groundtrack directions, and followed heading directions that were similar to their groundtrack directions when winds were lighter (Figure 6A). It is worth noting that had these birds experienced full-wind drift, and not compensated for the effects of wind displacement, our high-resolution analysis would have shown the opposite pattern to what is presented in Figure 6A. In the case of full-wind drift, the data would plot as near constant heading directions with highly variable groundtrack directions due to the extremely dynamic nature of the winds these birds flew through.

Bottom Line: 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.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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Geological Science, University of Canterbury, Christchurch, New Zealand.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus