Question about moult score
Hi, I have been doing ringing in Hong Kong for a few years. We tried to collect moult stage of birds for understanding their phenology. In general, we followed the BTO's practice to record the moult score, where "5" is assigned for new and fresh feather; and "0" for old feathers.
We sometimes found difficulty on assigning the moult score of birds, especially when the birds are having a full set of fully grown feather. Different ringers sometimes have dispute on deciding whether the feathers are old/fresh. Below is one commonly situation we encountered:
Two Plain Prinias of same age class were trapped. One with fully grown feathers in good condition although they are not newly fresh, i.e. not worn. Another individual has P1 moulting (say, score 2). Other flight feathers are in the same condition as the first individual. In this case, we may give "0" for all feathers for the first bird, and 2 for the second bird. However, when we do not have the second Prinia to compare, we might incorrectly give score "5" for the first bird because the feathers are in really good condition. How shall we improve our decision in a consistent way?
Thank you all.