Orientation and long-distance migration routes: an attempt to evaluate compass cue limitations and required precision
Author
Summary, in English
By computers imulationso f differentf lightr outesf or springm igratingK nots Calidris
canutusp, otentialo rientationa'ld angerz ones' werer evealedi n the equatora rea and
northo f the Arcticc ircle.A n evaluationo f the availabilityo f directionailn formation
duringm igratoryf lightsd emonstratedth e potentialh azardso f crossingt hese danger
zones. Investigationso f the directionalc onsequenceso f sun compass orientation
based upon an internalc lock in phase with local time at the departures ite showed
that such a mechanism would entail serious losses in distance and time. A simple
compensatingr uleb asedo n the rateo f changei n sun altitudew as foundt o workw ell
both at polar latitudes and in the equator area. The magnetic compass will become
inoperativec lose to the magnetice quatora nd the poles, thus restrictingth e availability
of directional information. Orientation by stellar cues will become impossible
during spring and summer at arctic latitudes. Simulations of potential migratory
routesa lso enablede xaminationo f the requiredp recisiono f compasss ystemsa nd it
was indicatedt hat necessaryo rientationa ccuracyr equiresm ore than one directional
selectionp er long-distancef light to ensure survival.I t is concludedt hat computer
simulations of flight tracks, based on ringing recoveries, visual observations, radar
studies and satellite telemetry may be a powerful tool helping to identify problems
which require future experimental attention.
canutusp, otentialo rientationa'ld angerz ones' werer evealedi n the equatora rea and
northo f the Arcticc ircle.A n evaluationo f the availabilityo f directionailn formation
duringm igratoryf lightsd emonstratedth e potentialh azardso f crossingt hese danger
zones. Investigationso f the directionalc onsequenceso f sun compass orientation
based upon an internalc lock in phase with local time at the departures ite showed
that such a mechanism would entail serious losses in distance and time. A simple
compensatingr uleb asedo n the rateo f changei n sun altitudew as foundt o workw ell
both at polar latitudes and in the equator area. The magnetic compass will become
inoperativec lose to the magnetice quatora nd the poles, thus restrictingth e availability
of directional information. Orientation by stellar cues will become impossible
during spring and summer at arctic latitudes. Simulations of potential migratory
routesa lso enablede xaminationo f the requiredp recisiono f compasss ystemsa nd it
was indicatedt hat necessaryo rientationa ccuracyr equiresm ore than one directional
selectionp er long-distancef light to ensure survival.I t is concludedt hat computer
simulations of flight tracks, based on ringing recoveries, visual observations, radar
studies and satellite telemetry may be a powerful tool helping to identify problems
which require future experimental attention.
Department/s
Publishing year
1998
Language
English
Pages
626-636
Publication/Series
Journal of Avian Biology
Volume
29
Issue
4
Document type
Journal article
Publisher
Wiley-Blackwell
Topic
- Ecology
- Probability Theory and Statistics
Status
Published
ISBN/ISSN/Other
- ISSN: 0908-8857