Amino Acid Specific Stable Nitrogen Isotope Values in Avian Tissues: Insights from Captive American Kestrels and Wild Herring Gulls

• Main Authors: Hebert, C.E. (Craig), Popp, B.N. (B. N.), Fernie, K.J. (K. J.), Ka'apu-Lyons, C. (C.), Rattner, B.A. (B. A.), Wallsgrove, N. (N.)
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Avian Studies
• Online Access: https://ir.library.carleton.ca/pub/15794

Through laboratory and field studies, the utility of amino acid compound-specific nitrogen isotope analysis (AA-CSIA) in avian studies is investigated. Captive American kestrels (Falco sparverius) were fed an isotopically characterized diet and patterns in δ15N values of amino acids (AAs) were compared to those in their tissues (muscle and red blood cells) and food. Based upon nitrogen isotope discrimination between diet and kestrel tissues, AAs could mostly be categorized as source AAs (retaining baseline δ15N values) and trophic AAs (showing 15N enrichment). Trophic discrimination factors based upon the source (phenylalanine, Phe) and trophic (glutamic acid, Glu) AAs were 4.1 (muscle) and 5.4 (red blood cells), lower than those reported for metazoan invertebrates. In a field study involving omnivorous he