Tree swallows (Tachycineta bicolor), have been studied as upper trophic‐level sentinels to assess reclamation strategies on the Alberta oil sands. Wetland reclamation incorporates tailings water and solids (from the extraction of bitumen from sand) into functioning aquatic ecosystems. Naphthenic acids (NAs) and polycyclic aromatic compounds (PACs) in tailing/reclamation material are constituents of concern for growth rate, reproductive function and immune function in tree swallows. Previous research indicated no differences in these endpoints from tailings additions; however, increased detoxification enzyme (EROD)
activity indicated exposure to xenobiotics from these tailings‐based sites. Stable isotope analyses are studied here to further define dietary exposure of tree swallows to oil sands constituents. Previous studies have shown trends of 13C depletion and 15N enrichment in benthic invertebrates from reclaimed wetlands on the oil sands. Because the majority (84%) of dietary items consumed by tree swallow nestlings is aquatic, the isotope signatures in tree swallows should provide evidence of exposure to oil sands constituents. Here, tree swallow feather and muscle tissues were examined to determine if stable isotopes could be used to distinguish dietary contributions from oil sands reclamation sites vs. reference sites containing no tailings materials.