Meeting Abstract

34.1  Monday, Jan. 5 08:15   Measuring corticosteroid metabolites in feathers: 1) optimizing methods to reduce artifacts BERK, S.A.*; BREUNER, C.W.; University of Montana; University of Montana sara.berk@umontana.edu

Since first publication in 2008, feather corticosterone (CORT) has become a widely used metric of stress physiology in birds. Feather CORT has been correlated with various facets of avian biology including breeding success, coloration, and nutritional status. However, there remain substantial questions about how to most accurately measure feather CORT. Notably, we find that across species the amount of CORT (pg/mm or mg) declines exponentially with increasing amounts of feather. In fecal CORT methods, increasing the methanol to mg feces ratio has accounted for this problem. Here, we attempted to account for this by manipulating the methanol to feather ratio across both mg (feather weight) and mm (feather length). Unfortunately, pg CORT/mg or mm of feather continued to decline even at extremely high volumes of methanol, and this effect persisted across a wide range of feather weights and lengths. We will discuss considerations for measuring feather CORT in light of this, and make recommendations for future work.