Tracing origins and nutrient allocations in migrating birds and insects using compound-specific isotope techniques

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Migratory birds, insects and other animals often move over vast distances and between continents during their annual cycles. This presents immense challenges for their effective conservation and understanding of the factors influencing their survival and successful reproduction. Diet and nutrition play a fundamental role in determining the success of migratory animals because migrants need to fuel their journeys which may be hundreds or thousands of kilometers. During these travels, animals often need to stopover at key sites where they can rest and refuel. In reaching their destinations, they often encounter entirely different foodwebs and need to adjust their diets and foraging accordingly. Migrants that travel to breed also are able to carry nutrients with them that ultimately can be transferred to their offspring while other organisms like migratory Monarch Butterflies need to arrive on their wintering grounds in Mexico with enough fat reserves to last them through the winter fasting period. It is important to trace the importance of nutrient pathways to migratory organisms. Such knowledge will allow much more informed conservation of wildlife important to Canadians by identifying critical habitats where nutrients are derived. The anticipated information will also help us assess the susceptibility of migrants to current and anticipated global change. I have developed the use of naturally occurring fingerprints in foodwebs known as stable isotopes (of several elements) to trace origins and use of nutrients in wild birds and insects. My current proposal is to move this area of research to a new level, from analyses of bulk tissues like feathers into the realm of individual amino acids and lipids. This will allow more precise tracing and follows from recent breakthroughs in this field based on the discovery that isotope ratios in individual compounds can provide more precise information of trophic level and source of feeding. This proposal will support graduate thesis projects to examine the use of amino acid (primarily glutamate and phenylalanine) and whole lipid stable isotope analyses as fingerprints to evaluate 1) long-term dietary reconstruction in migratory birds (thrushes and shorebirds), 2) origins of stored lipid reserves used by migratory insects for overwinter survival and 3) contributions of stored vs. locally acquired nutrients for reproduction in birds that travel to breed.