Potential for gulls to transport bacteria from human waste sites to beaches

•Gull cloacae and feces samples contained the human specific marker, HF 183.•Markers for gull and human contamination showed spatial and temporal overlap.•Radio-telemetry supports potential for gulls to disperse human-associated microbes.•Gulls may act as transport vectors of human pathogens.•Gull4 was a more sensitive source-tracking marker when compared to Gull2. [Display omitted] Contamination of recreational beaches due to fecal waste from gulls complicates beach monitoring and may pose a risk to public health. Gulls that feed at human waste sites may ingest human fecal microorganisms associated with that waste. If these gulls also visit beaches, they may serve as vectors, transporting fecal microorganisms to the beach where they may subsequently contaminate sand and water. In this study, samples collected from landfills, treated wastewater storage lagoons, and public beaches demonstrated a spatial and temporal overlap of markers for gull and human-associated microorganisms. In addition, markers for gull, fecal indicator bacteria, and the human-associated marker, HF183, were detected in gull feces and cloacae samples. Further, HF183 was detected in cloacae samples from gulls that were documented by radio-telemetry traveling between human waste sites and public beaches. This study highlights the potential for gulls that visit human waste sites to disperse human-associated microorganisms in the beach landscape.