Sökning: "Flight directions"

Visar resultat 1 - 5 av 11 avhandlingar innehållade orden Flight directions.

1. 1. Flight Behaviour of Passerines on Nocturnal Migration

   Författare :Cecilia Nilsson; Evolutionär ekologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Bird migration; Passerines; Flight Behaviour; Tracking radar; Optimal migration; Flight speed; Airspeed; Wind drift; Nocturnal migration; Coastline effects; Flight directions; Reverse migration;

   Sammanfattning : Many passerines migrate during the night and at high altitudes, making their migration difficult to observe. By using tracking radars we have been able to make exact observations of the flight behaviour of passerines on nocturnal migration, which has enabled us to test several hypotheses about adaptive values and constraints regarding migratory behaviour in different ecological contexts. LÄS MER

3. 2. Flight strategies in migrating birds: when and how to fly

   Författare :Martin Green; Biodiversitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; geese; waders; terns; Animal ecology; Djurekologi; wind tunnel; radio telemetry; satellite telemetry; radar; formation flight; flight speed adjustment; wind drift; energy savings; departure decisions; bird migration; wind;

   Sammanfattning : Wind has a profound influence on migrating birds since it inevitably will influence travel time and energy expenditure. In this thesis I investigate how migrating birds are affected by, and use winds. LÄS MER

4. 3. Stopover behaviour in migratory songbirds: timing, orientation and departures

   Författare :Sissel Sjöberg; Funktionell zoologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; flight duration; orientation; departure timing; stopover behaviour; stopover duration; flight behaviour; reverse migration; route choice; compass calibration; passerines; Bird migration;

   Sammanfattning : Songbird migrants use stopovers between flight bouts to rest and refuel for the upcoming flights. Behaviours affecting where, when and how long to stay at stopover sites will affect how successful the overall migration will be, which has significant consequences for the overall fitness and mortality of the birds. LÄS MER

5. 4. There and Back Again - nocturnal migratory behaviour of birds during spring and autumn

   Författare :Håkan Karlsson; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; migration; seasons; flight; orientation; navigation; behaviour; strategies; birds; nocturnal;

   Sammanfattning : This dissertation explores the migratory behaviour of nocturnally migrating passerines and common swifts (Apus apus). Birds passing Lund (southern Sweden) and Abisko (northernmost Scandinavia) where sampled using tracking radar. The aim has been to investigate potential diverging strategies between spring and autumn migration. LÄS MER

7. 5. Adaptive flexibility in migratory behaviour of shorebirds

   Författare :Johanna Grönroos; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Bird migration; compensation; departure decision; flight distance; migration speed; migration strategy; orientation; shorebird; stopover; wind drift; wind selectivity;

   Sammanfattning : The phenomenon of bird migration has long fascinated us humans and it has prompted questions like where do they go or come from and how do they find their way? Arctic shorebirds are well known for their spectacular long-distance migrations with some species travelling more than 10 000 km every spring and autumn, and some even cover this distance in one single nonstop flight. The aim of my thesis was to investigate the flexibility of Arctic shorebirds when it comes to orientation behaviour, departure behaviour and migration strategy. LÄS MER