One-Direction Orientation versus Goal Area Navigation in Migratory Birds

Rabøl, Jørgen

doi:10.2307/3543481

Cited by 55 publications

(47 citation statements)

References 3 publications

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“…We have shown that, in all probability, these movements are not caused by wind drift. We also consider it highly unlikely that these movements are temporary and random deviations from an intended orientation in the east-south-east sector, re£ecting uncertainty and variability in the accuracy of the birds' orientation system (see RabÖl (1978), Mouritsen (1998) and Alerstam (1999) for details about varying courses in migration by vector summation). The trajectories of the migrants, as recorded by radar over 3^10 km distances, were generally very straight, showing no signs of important short-term directional variability.…”

Section: Discussionmentioning

confidence: 99%

Bird orientation at high latitudes: flight routes between Siberia and North America across the Arctic Ocean

Alerstam

Guðmundsson

1999

Proc. R. Soc. Lond. B

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Bird migration and orientation at high latitudes are of special interest because of the di¤culties associated with di¡erent compass systems in polar areas and because of the considerable di¡erences between £ight routes conforming to loxodromes (rhumblines) or orthodromes (great circle routes). Regular and widespread east-north-east migration of birds from the northern tundra of Siberia towards North America across the Arctic Ocean (without landmark in£uences) were recorded by ship-based tracking radar studies in July and August. Field observations indicated that waders, including species such as Phalaropus fulicarius and Calidris melanotos, dominated, but also terns and skuas may have been involved. Analysis of £ight directions in relation to the wind showed that these movements are not caused by wind drift. Assuming possible orientation principles based on celestial or geomagnetic cues, di¡erent £ight trajectories across the Arctic Ocean were calculated: geographical loxodromes, sun compass routes, magnetic loxodromes and magnetoclinic routes. The probabilities of these four alternatives are evaluated on the basis of both the availability of required orientation cues and the predicted £ight paths. This evaluation supports orientation along sun compass routes. Because of the longitudinal time displacement sun compass routes show gradually changing compass courses in close agreement with orthodromes. It is suggested that an important migration link between Siberia and North American stopover sites 1000^2500 km apart across the Arctic Ocean has evolved based on sun compass orientation along orthodrome-like routes.

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Section: Discussionmentioning

confidence: 99%

Bird orientation at high latitudes: flight routes between Siberia and North America across the Arctic Ocean

Alerstam

Guðmundsson

1999

Proc. R. Soc. Lond. B

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“…If the Ospreys were guided by the principles of vector orientation, as discussed by Rabøl (1978), Mouritsen (1998) and Alerstam (2000), one would expect a reduced directional scatter with increased segment length. However, there was no significant correlation between angular deviation and segment length, either when considering all individuals (r s = −0.03, n =13, n.s., Spearman rank correlation test) or when excluding the juveniles (r s = −0.17, n =11, n.s.…”

Section: Orientationmentioning

confidence: 99%

“…There is no such tendency of a leftward course change, making orientation along magnetic loxodromes unlikely. Rabøl (1978) and Mouritsen (1998) demonstrated how migrants drawing their orientation during each flight step from a circular probability distribution with a fairly large scatter will, by the effect of vector summation over many flight steps, produce resulting long-distance migratory directions with a much more restricted angular scatter. With a directional concentration of each step corresponding to a mean vector length r, the bird would follow a circuitous route on average 1/r times longer than the straight-line distance to the destination (cf.…”

Section: Orientationmentioning

confidence: 99%

Satellite tracking of Swedish Ospreys Pandion haliaetus: autumn migration routes and orientation

Hake¹,

Kjellén²,

Alerstam³

2001

Journal of Avian Biology

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Autumn migration routes and orientation of Swedish Ospreys Pandion haliaetus were studied by satellite tracking of 18 birds. Of these, 13 could be followed during the entire migration (6 females, 5 males and 2 juveniles). Most birds migrated across western and central Europe to winter in tropical West Africa. However, one juvenile flew to Cameroon and one female used a very easterly route and reached Mozambique. On average, the birds travelled a total distance of about 6700 km, with little variation except for the female wintering in Mozambique, who travelled more than 10 000 km. Of 21 stopovers (of >1 day), only five were made south of 45°N; three of these in Africa. Females departed before males and juveniles and flew to a stopover site they probably were familiar with. After 3–4 weeks there, they continued to their wintering grounds. Also males and juveniles usually made one or more stopovers. Adults seemed to travel to a known wintering site, where they remained stationary, whereas juveniles were more mobile after reaching tropical regions, probably looking for good wintering sites. Males generally left the breeding area in directions similar to the mean migratory direction, whereas a few females departed in diverging initial directions. Apart from these diversions, adult Ospreys followed very straight migratory routes, with overall mean directions of 185–209° and with mean angular deviations of 6–33°. Some juveniles also departed in diverging directions. Moreover, young birds tended to show a larger variability in orientation. Thus, the Ospreys kept a fairly straight direction and did not avoid geographical obstacles such as mountain ranges and desert areas. However, they seemed reluctant to cross large water bodies. There was no correlation between angular deviation and length of the migrational segment, indicating that the principles of orientation by vector summation may not be valid for Osprey migration. Moreover, the geographic direction of migration did not vary in accordance with variations in the magnetic declination, suggesting that the Ospreys did not orient along magnetic loxodromes.

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“…There are two other extant models of bird migration: the clock-and-compass model (Perdeck 1958, Dorst 1962, and the goal-area navigation model (Rabol 1970(Rabol , 1978. According to the clock-and-compass model, a young bird migrates for a fixed time in a fixed direction (time and direction being innately programmed).…”

mentioning

confidence: 99%

The significance of the Lesser Black-backed Gull to models of bird migration

Baker

1980

Bird Study

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One-Direction Orientation versus Goal Area Navigation in Migratory Birds

Cited by 55 publications

References 3 publications

Bird orientation at high latitudes: flight routes between Siberia and North America across the Arctic Ocean

Bird orientation at high latitudes: flight routes between Siberia and North America across the Arctic Ocean

Satellite tracking of Swedish Ospreys Pandion haliaetus: autumn migration routes and orientation

The significance of the Lesser Black-backed Gull to models of bird migration

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