The Relationship between wing area and raggedness during molt in the willow warbler and other passerines

摘要

Molt involves increased metabolic cost due to the energy required to synthesize new feathers and increased cost of thermoregulation because the insulation capacity is re- duced. Flight cost is also increased because wing span and wing area are reduced when remiges are missing or growing. However, data n the reduction of wing area during molt (necessary for calculating aerodynamic performance) is lacking. I show how standard molt scores (converted into a raggedness score) can be used to estimate the reduction o wing area due to molt in Willow Warblers (Phyloscopus trochilus) and selected other passerines.