Sökning: "roosting flight"

Hittade 4 avhandlingar innehållade orden roosting flight.

  1. 1. Always on the wing - Fluid dynamics, flight performance and flight behavior of common swifts

    Författare :Per Henningsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Apus apus; aerodynamics; animal flight; kinematics; vortex wake; digital particle image velocimetry; DPIV; common swift; tracking radar; wind tunnel; migration; roosting flight;

    Sammanfattning : The aerodynamics and kinematics behind the flight of animals are relatively unknown. Although animal flight has been studied for several hundreds of years, it is only in recent time that we have the technical abilities to study the mechanistic basis of animal flight. LÄS MER

  2. 2. Feathers by day, membranes by night - Aerodynamic performance in bird and bat flight

    Författare :Florian Muijres; Evolutionär ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; animal flight; aerodynamics; vortex wake; actuator disk; flight performance; span efficiency; bird; bat; wind tunnel; PIV; Pied Flycatcher; Glossophaga soricina; Leptonycteris yerbabuenae;

    Sammanfattning : The efficiency and performance of a flying animal is directly related to the aerodynamics around its body and flapping wings. Here, I have developed methods for quantifying the wake dynamics around a flying animal. The results are used to estimate the aerodynamic performance of flapping flight. LÄS MER

  3. 3. Bird orientation: external cues and ecological factors

    Författare :Johan Bäckman; Evolutionär ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; tracking radar; Emlen funnel.; Animal ecology; Djurekologi; oscillatory orientation; roosting flight; scatter; concentration; heading; cue calibration; light dependent; magnetoreception; subcutaneous fat stores; body condition; energetics; geomagnetic field; visual cues; orientation; birds; migration;

    Sammanfattning : Birds are generally capable of accurate orientation. In this thesis I present studies about the external cues and the ecological factors that influences bird orientation. A multitude of environmental cues are used to select and maintain a proper direction. LÄS MER

  4. 4. On the importance of farmland as stopover habitat for migrating birds

    Författare :Juliana Dänhardt; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; conservation; bird migration; agriculture; stopover ecology; Golden plover; Pluvialis apricaria; landscape heterogeneity; organic farming; food availability; earthworms;

    Sammanfattning : Agricultural intensification has led to dramatic population declines among many farmland bird species. Negative effects of intensive farming in terms of decreased local habitat quality or structural simplification of farmland landscapes have reduced both reproductive outcome and winter survival of many species. LÄS MER