Table 1.

Overview of experimental conditions

Individual orientation behavior Group orientation behavior Group orientation behavior doubled angles
nrindividual * s.d.Randomnαrgroup P95% conf. intervalnαrgroup P
Sun visible (2003)160.440.23016202°0.80<0.001182–222°
Sun visible, overpainted DRA (2003)200.470.28020208°0.58<0.001178–238°
Sun visible (2004)330.490.26429166°0.61<0.001142–190°
Sun visible, clock-shifted +6 h (2004)210.510.28219262°0.66<0.001235–289°
Sun visible, clock-shifted +6 h, overpainted DRA (2004)280.460.32424252°0.48<0.01217–287°
Complete overcast simulation270.260.17522134°0.220.3522140°/320°0.200.42
44° visual field of sky
   Geographical orientation
      Morning300.350.22525354°0.230.2725151°/331°0.180.45
      Afternoon210.350.25318309°0.090.861894°/274°0.360.10
      Combined data510.350.23843345°0.160.3943116°/296°0.140.42
   Orientation towards e-vector axis (E–W)
      MorningSame as for geographical orientation25210°0.150.572535°/215°0.190.41
      Afternoon1859°0.07>0.901843°/223°0.300.20
      Combined data43198°0.06>0.904339°/219°0.230.10
      90° turn of lid§100.72<0.01329–39°
44° polarized light stimulus (sun shades up)
   Time-compensated orientation480.370.2454389°/269°0.230.13
   Orientation towards e-vector axis (N–S)43231°0.140.4343174°/354°0.200.20
   Flight direction change after 90° turn of polarizer16348°0.61<0.01316–20°
85° polarized light stimulus (no sun shades)
   Time-compensated orientation490.410.2564371°/251°0.260.06
   Orientation towards e-vector axis (N–S)43115°0.230.194342°/222°0.250.11
   Flight direction change after 90° turn of polarizer290.57<0.001342–28°
85° polarized light stimulus (sun shades up)
   Time-compensated orientation380.320.2163289°/269°0.140.56
   Orientation towards e-vector axis (N–S)32288°0.250.1632100°/280°0.160.47
   Flight direction change after 90° turn of polarizer514°0.660.11321–67°
  • * Mean directedness of individual flights

  • number of flights where rsing<0.1

  • mean directedness of experimental group

  • § control experiment for 90° turn of polarizers