Flying at No Mechanical Energy Cost: Disclosing the Secret of Wandering Albatrosses

Sachs, Gottfried; Traugott, Johannes; Nesterova, Anna; Dell’Omo, Giacomo; Kümmeth, Franz; Heidrich, Wolfgang; Vyssotski, Alexei L.; Bonadonna, Francesco

doi:10.1371/journal.pone.0041449

Cited by 89 publications

(79 citation statements)

References 21 publications

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“…Error bars represent standard deviation. The regression equation and coefficient of determination are given a dynamic soaring technique allowing them to cover large distances with low energetic cost (Richardson 2011, Sachs et al 2012. Our results thus probably reflect the ability of these birds to take advantage of the easterly winds in the warmer oceanic zone to move westward, and then to come back quickly to the colony on a more direct trajectory using the stronger and fairly constant westerlies blowing in the cooler latitudes (Weimerskirch et al 1993(Weimerskirch et al , 2012.…”

Section: Variability In Distribution and Movementsmentioning

confidence: 74%

Stage-dependent distribution of the Critically Endangered Amsterdam albatross in relation to Economic Exclusive Zones

Thiebot¹,

Delord²,

Marteau³

et al. 2014

Endang. Species. Res.

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Long-lived animals typically exhibit several stages throughout their life cycle during which their distribution may vary substantially, which may challenge the relevance of protection measures. Here we surveyed individual movements of the Critically Endangered Amsterdam albatross from Amsterdam Island, southern Indian Ocean, throughout its life cycle. Our goal was to identify, from the areas visited by the albatrosses, which coastal states share responsibility in regulating industrial fishing in their Exclusive Economic Zones (EEZs) in order to promote the preservation of this species. Using stage-relevant tracking techniques (satellite tags, GPS and GLS loggers), we surveyed 361 at-sea trips by 93 individuals over 9 yr, covering incubation, brooding, chick-rearing, sabbatical, failed-breeding, juvenile and immature stages. Our data show that Amsterdam albatrosses exhibit a wide and variable foraging radius (from 326 ± 193 km during brooding to 5519 ± 766 km for immatures) and at-sea distribution across stages, putting them beyond the French EEZ of Amsterdam Island for all or part of the trips surveyed in each stage, and even outside the Indian Ocean when breeding. In all, the breeding versus non-breeding albatrosses visited the EEZs of 1 to 3 versus 3 to 4 countries, respectively. Only breeders visited the EEZs of Madagascar and Mauritius, while only non-breeders visited the EEZs of Australia, South Africa and Namibia. This study stresses the relevance to conservation of obtaining synoptic information on the distribution of threatened species, especially regarding the breeding versus nonbreeding categories of populations.

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Section: Variability In Distribution and Movementsmentioning

confidence: 74%

Stage-dependent distribution of the Critically Endangered Amsterdam albatross in relation to Economic Exclusive Zones

Thiebot¹,

Delord²,

Marteau³

et al. 2014

Endang. Species. Res.

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“…Second, potential sources of error that might be related to the characteristics of soaring flight of the seabirds should be considered. The unique dynamic soaring flight pattern used by shearwaters and albatrosses not only zigzags in the horizontal direction but also undulates in the vertical direction (23,24,30). Therefore, the variation in ground speed includes the decrease and increase of ground speed associated with the gain and loss of altitude.…”

Section: Resultsmentioning

confidence: 99%

“…This may cause the estimated wind speed to deviate from the true wind speed experienced by the bird. However, studies of dynamic soaring flight show that potential energy associated with flight altitude is much smaller than the kinetic energy associated with fluctuating ground speed, indicating that wind resistance and assistance dominates ground speed fluctuation (23,24). Another error can be caused by albatrosses and shearwaters adjusting their air speed in relation to head and tail winds, with air speed increasing in head winds (21,28), because here we assumed that the bird flew in a constant air speed in each section.…”

Section: Resultsmentioning

confidence: 99%

“…It is also comparable to 10-min to 1-h interval of in situ measurement from buoys and weather stations. The advantage of using these seabirds is the characteristic dynamic soaring flight, which relies heavily on the energy extracted from wind (23,24), indicating the strong influence of wind velocity to their ground speed. This flight strategy results in a tortuous trajectory including more than 10 soaring cycles of 10-20 s, providing sufficient variation of flight direction in a short time period that enabled a successful fitting of a sinusoidal curve ( Fig.…”

Section: Estimating Ocean Surface Wind Using Soaring Seabirdsmentioning

confidence: 99%

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Flight paths of seabirds soaring over the ocean surface enable measurement of fine-scale wind speed and direction

Yonehara

Goto

Yoda

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Ocean surface winds are an essential factor in understanding the physical interactions between the atmosphere and the ocean. Surface winds measured by satellite scatterometers and buoys cover most of the global ocean; however, there are still spatial and temporal gaps and finer-scale variations of wind that may be overlooked, particularly in coastal areas. Here, we show that flight paths of soaring seabirds can be used to estimate fine-scale (every 5 min, ∼5 km) ocean surface winds. Fine-scale global positioning system (GPS) positional data revealed that soaring seabirds flew tortuously and ground speed fluctuated presumably due to tail winds and head winds. Taking advantage of the ground speed difference in relation to flight direction, we reliably estimated wind speed and direction experienced by the birds. These birdbased wind velocities were significantly correlated with wind velocities estimated by satellite-borne scatterometers. Furthermore, extensive travel distances and flight duration of the seabirds enabled a wide range of high-resolution wind observations, especially in coastal areas. Our study suggests that seabirds provide a platform from which to measure ocean surface winds, potentially complementing conventional wind measurements by covering spatial and temporal measurement gaps.biologging | dynamic soaring | satellite scatterometer | GPS | meteorology R ecently, remote-sensing systems used to record atmospheric circulation have been developed. Satellite-borne scatterometers estimate ocean surface wind velocities each day covering the majority of the global ocean. These wide-range wind data in combination with refined ocean models are used in numerical weather predictions and describe the oceanographic features more accurately (1-3). Buoys scattered over the ocean also measure fine-time resolution in situ surface winds and are used in validating remote-sensing measurements and are assimilated into model analyses (4, 5). However, because wind data are only acquired twice per day by each satellite and buoys have limited spatial coverage, finer-scale changes of hours to days in local wind conditions could be overlooked. In addition, in coastal areas, where high biological productivity is associated with ocean and atmosphere circulation patterns (6), wind data are lacking due to variations in wind and wave caused by complex topographic effects that satellites have difficulty measuring (5,7,8). Obtaining in situ high-resolution atmospheric and oceanographic data to fill these spatial and temporal observation gaps would deepen our understanding of physical processes relevant to interactions between the atmosphere and ocean, contribute to improved atmospheric and ocean model analyses (7,8), and reveal detailed structure that remains unresolved by using conventional methods (9).The recent development of miniaturized animal-borne data loggers presented a capability to use animals as indicators of environmental variables. The extensive movement range and locomotion ability of marine mammals and seabirds ena...

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“…As a result, the birds can fly at virtually no cost when compared with flapping flight (Weimerskirch et al, 2000). By applying dynamic soaring (Sachs, 2005;Sachs et al, 2012), the birds gain access to an unlimited external energy source in terms of the shear wind above the sea surface. The unique advantage of having an unlimited energy source is due to the fact that there are permanently strong winds in the areas in which albatrosses live (Suryan et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Experimental verification of dynamic soaring in albatrosses

Sachs

Traugott

Nesterova

et al. 2013

Journal of Experimental Biology

106

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SUMMARYDynamic soaring is a small-scale flight manoeuvre which is the basis for the extreme flight performance of albatrosses and other large seabirds to travel huge distances in sustained non-flapping flight. As experimental data with sufficient resolution of these small-scale movements are not available, knowledge is lacking about dynamic soaring and the physical mechanism of the energy gain of the bird from the wind. With new in-house developments of GPS logging units for recording raw phase observations and of a dedicated mathematical method for postprocessing these measurements, it was possible to determine the small-scale flight manoeuvre with the required high precision. Experimental results from tracking 16 wandering albatrosses (Diomedea exulans) in the southern Indian Ocean show the characteristic pattern of dynamic soaring. This pattern consists of four flight phases comprising a windward climb, an upper curve, a leeward descent and a lower curve, which are continually repeated. It is shown that the primary energy gain from the shear wind is attained in the upper curve where the bird changes the flight direction from windward to leeward. As a result, the upper curve is the characteristic flight phase of dynamic soaring for achieving the energy gain necessary for sustained non-flapping flight.

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Flying at No Mechanical Energy Cost: Disclosing the Secret of Wandering Albatrosses

Cited by 89 publications

References 21 publications

Stage-dependent distribution of the Critically Endangered Amsterdam albatross in relation to Economic Exclusive Zones

Stage-dependent distribution of the Critically Endangered Amsterdam albatross in relation to Economic Exclusive Zones

Flight paths of seabirds soaring over the ocean surface enable measurement of fine-scale wind speed and direction

Experimental verification of dynamic soaring in albatrosses

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