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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

Wind vector analysis.Relationship between wind velocity and juvenile osprey movement velocity perpendicular to (A, B) and parallel to (C, D) the mean ground track direction of migration track segments. Wind velocities were determined for one-hourly GPS locations (A, C) using a dynamic regional mesoscale meteorological model. Track segment mean velocities (B, D) ±1σ error bars are also shown. Track segment colors and symbols as in Figure 1. Dashed lines represent 1:1 relationship.
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pone-0114557-g004: Wind vector analysis.Relationship between wind velocity and juvenile osprey movement velocity perpendicular to (A, B) and parallel to (C, D) the mean ground track direction of migration track segments. Wind velocities were determined for one-hourly GPS locations (A, C) using a dynamic regional mesoscale meteorological model. Track segment mean velocities (B, D) ±1σ error bars are also shown. Track segment colors and symbols as in Figure 1. Dashed lines represent 1:1 relationship.

Mentions: In contrast to juvenile ospreys migrating over land [1], our results demonstrate that juvenile ospreys migrating over open ocean fully compensate for the effects of perpendicular wind drift (Figure 4A-B). Our analyses reveal that there is no significant correlation between the birds' perpendicular movement velocities and corresponding perpendicular wind velocities (p = 0.734; ANOVA; F = 0.12; dfreg = 1; dferr = 242; α = 0.05). Despite experiencing perpendicular winds as strong as 40 km/h, both from the left and from the right of their forward movement direction, the birds we tracked were rarely off course by more than 10 km (Figure 4A). Thus, we reject the hypothesis that juvenile ospreys experience full wind drift during long-distance migration over open ocean. Rather, the data we report demonstrate that not only did these birds compensate for wind drift, but they overcompensated (i.e. perpendicular movement and wind velocities with opposite signs) for the effects of perpendicular wind drift more than 51% of the time.


Juvenile Osprey Navigation during Trans-Oceanic Migration.

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

Wind vector analysis.Relationship between wind velocity and juvenile osprey movement velocity perpendicular to (A, B) and parallel to (C, D) the mean ground track direction of migration track segments. Wind velocities were determined for one-hourly GPS locations (A, C) using a dynamic regional mesoscale meteorological model. Track segment mean velocities (B, D) ±1σ error bars are also shown. Track segment colors and symbols as in Figure 1. Dashed lines represent 1:1 relationship.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0114557-g004: Wind vector analysis.Relationship between wind velocity and juvenile osprey movement velocity perpendicular to (A, B) and parallel to (C, D) the mean ground track direction of migration track segments. Wind velocities were determined for one-hourly GPS locations (A, C) using a dynamic regional mesoscale meteorological model. Track segment mean velocities (B, D) ±1σ error bars are also shown. Track segment colors and symbols as in Figure 1. Dashed lines represent 1:1 relationship.
Mentions: In contrast to juvenile ospreys migrating over land [1], our results demonstrate that juvenile ospreys migrating over open ocean fully compensate for the effects of perpendicular wind drift (Figure 4A-B). Our analyses reveal that there is no significant correlation between the birds' perpendicular movement velocities and corresponding perpendicular wind velocities (p = 0.734; ANOVA; F = 0.12; dfreg = 1; dferr = 242; α = 0.05). Despite experiencing perpendicular winds as strong as 40 km/h, both from the left and from the right of their forward movement direction, the birds we tracked were rarely off course by more than 10 km (Figure 4A). Thus, we reject the hypothesis that juvenile ospreys experience full wind drift during long-distance migration over open ocean. Rather, the data we report demonstrate that not only did these birds compensate for wind drift, but they overcompensated (i.e. perpendicular movement and wind velocities with opposite signs) for the effects of perpendicular wind drift more than 51% of the time.

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