Use of Great Lakes recreational beaches and human-waste sites by ring-billed gulls

Larus delawarensis (Ring-billed Gull) populations have increased >4% annually in the Great Lakes region since 2003. Gull-human interactions and conflicts have similarly increased, particularly concerning human health and safety issues related to gull feces deposited at recreational beaches. During June-August 2013, we conducted a radiotelemetry study of Ring-billed Gulls in a Lake Michigan coastal region to determine patterns of habitat use and movement between recreational beaches and human infrastructure by gulls. Of 14 individuals relocated, we found Ring-billed Gulls selected recreational beaches and landfill sites and avoided agricultural fields. We found 5 of 14 gulls made a minimum of 2 roundtrips between beaches and landfills over the study period. Gulls may serve as transport vectors for bacteria and other pathogens from human-waste sites to areas of probable human contact and concentration, such as public recreational beaches. As such, pathogen distribution and connectivity within a landscape could be established, maintained, and enhanced by gull movements. Managers may need to implement exclusion tools for gulls at both of these sites to maintain human-health standards.