Meeting Abstract

P2.11  Friday, Jan. 4  Tracking Eared Grebe migration using fatty acid signature analysis GAFNEY, J.M.; University of San Diego jgafney-09@sandiego.edu

Dietary tracers within animal tissues have been successfully used to link migratory predators with specific feeding locations. Fatty acid signature analysis (FASA) is one such technique for determining trophic relationships within an ecosystem. Identification of specific prey fatty acids in the adipose tissue of predators can hypothetically be used to identify where migratory species fed before migration. To establish the utility of FASA in tracking migratory movements, Eared Grebes (Podiceps nigricollis) and their prey were collected from two consecutive stopover points � Salton Sea and Great Salt Lake � along their vernal migration route in 2006. Fatty acid signatures from grebe adipose tissue and from prey items were evaluated and compared to determine whether Salton Sea prey fatty acid signatures were detectable in individual Great Salt Lake grebes, indicating which grebes stopped at Salton Sea on the way to Great Salt Lake. Preliminary results showed no indication that grebes sampled at Great Salt Lake foraged at Salton Sea; specific feeding locations within Great Salt Lake, however, could be identified using fatty acid signatures. Results suggest that the use of FASA to track migration in Eared Grebes shows promise, but because of the high annual variability in the use of Salton Sea by Eared Grebes and a recent dramatic decline in the proportion of grebes stopping there, a larger sample size and identification of more fatty acids may be necessary to demonstrate the applicability of FASA to tracking Eared Grebe migration.