Table 1.

Orientation behaviour of European robins under red light

Grand mean vector
Test conditionPeak λ (nm)Intensity (mW m-2)Light condition before testingNαnrnSignificant difference to control
Effect of pre-exposure to red light on the orientation behavior under red light
C`White'24.4`White' light120.96***
R6352.1`White' light1146°0.34ns***
RX63513.0`White' light1137°0.34ns***
RpeR6352.1635 nm red1125°0.81***NS
RpeRX63513.0635 nm red1232°0.62****
RpeG5652.4635 nm red12357°0.56***
R26452.1`White' light11154°0.33ns**
Comparing the aftereffect of exposure to red light with that of exposure to darkness
C`White'24.4`White' light1215°0.81***
R6451.8`White' light12278°0.30ns**
G5652.1`White' light110.94***NS
RpeR6451.8635 nm Red11358°0.79***NS
RpeG5652.1635 nm Red11357°0.49nsNS
DpeR6451.8Total darkness12322°0.24ns*
DpeG5652.1Total darkness1117°0.88***NS
Seasonal change in heading between spring and autumn migration
C`White'24.4`White' light16201°0.64***
G5652.1`White' light16200°0.68***NS
RepR6451.8635 nm red15181°0.62**NS
  • Peak λ, peak wavelength of LED spectrum; N, number of birds tested; αn, direction of the grand mean vector; rn, length of the grand mean vector; asterisks at rn indicate significant directional preference by the Rayleigh test; the asterisks in the Significance column indicate significance of the difference to the control tests under `white' light. Significance levels: *P<0.05; **P<0.01; ***P<0.001; NS, not significant (P>0.05).