Bioaccumulation of heavy metals and diet changes between seasons in wild songbird populations are basic but important information needed to make informed decisions about conservation efforts. I evaluated heavy metal concentrations in migratory Great Crested Flycatchers (Myarchus crinitis) and resident Northern Cardinals (Cardinalis cardinalis) along with trophic level changes in diet through stable isotope analysis between breeding and non-breeding seasons. Blood and feather samples were collected in South Carolina from April 2016-May 2017. Heavy metal concentrations were low compared to other related species but currently, it is unknown whether these levels have no physiological effect on individuals. Flycatchers forage at a higher trophic level than cardinals based on higher 15N values in blood and feather samples. Both cardinals and flycatchers trophic level unexpectedly increased between breeding and non-breeding seasons. Further research is needed to connect diet, exposure to contaminants, and fitness of migratory and resident birds.
