Table 1.

Summary of breaking data for the feather barbs

VariableMeans.d.s.e.m.N
Force (Fbrk) (N)1.150.560.042176
Extension (lbrk) (mm)0.610.230.017176
Stress (σbrk) (MN m−2)281766.1156
Strain (ϵbrk)0.0600.0240.0018176
Toughness (T) (MJ m−3)10.16.70.54156
  • Data for unmelanized and melanized barbs are pooled since no colour-based differences were detected (see figures and text).