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Abstract

Parasites can influence important ecosystem characteristics, such as biomass,Ìýbiodiversity, food webs, and species interactions. Parasites of birds, in particular, offer a uniqueÌýopportunity to test questions about parasites with complex life cycles (those that require moreÌýthan one host for completion) and how host life history traits affect parasitic infections. ForÌýexample, there is evidence that migratory versus non-migratory behavior in birds can affect theÌýparasites present in a host, although whether migratory birds have more or fewer parasites isÌýunclear. To help address these knowledge gaps, we collaborated with airports, animalÌýrescue/rehabilitation centers, and hunter check stations in the Bay Area of California to collectÌý57 raptors, waterfowl and herons for parasitological analysis. We performed detailed dissectionsÌýof the gastro-intestinal tract and identified 64 taxa of parasites: 5 acanthocephala (thorny headedÌýworms), 24 nematoda (roundworms), 8 cestoda (tapeworms), and 27 trematoda (flatworms). WeÌýthen used generalized linear mixed modeling to determine how life history traits influencedÌýparasite richness (number of taxa present) among bird hosts. We found associations with clutchÌýsize, diet and migratory status: parasite richness was greater in birds that were migratory, hadÌýliterature and has been linked to immune system function and parasite exposure respectively,Ìýwhereas the effect of migration supports one of the two opposing hypotheses which are a topic ofÌýongoing debate. These results add to the growing knowledge of how host life history canÌýinfluence parasitic infections, especially with respect to the role of migration on parasiteÌýrichness.