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Open Access Publications from the University of California

The Chicago Ring-Billed Gull Damage Management Project


The population of ring-billed gulls in the upper Midwest has increased exponentially in recent decades leading to a variety of conflicts including property damage, negative economic impacts, threats to human safety, and potential threats to human health. Some studies have suggested a link between gull fecal droppings and elevated Escherichia coli levels, which result in swim advisories and bans on public beaches. The objectives of the Chicago ring-billed gull damage management project were to reduce the local production of ring-billed gulls, to evaluate the affects limiting gull production has on gull use of beaches, and to reduce the severity of conflicts with gulls including the issuance of swim advisories and swim bans. Between 2007 and 2009, we applied corn oil to 52 - 80% of nests in 2 large gull colonies in Chicago and successfully reduced hatching success and subsequent fledging of 18,000 - 42,000 gulls per year without causing colony abandonment. Fewer hatch year gulls were observed in 2009 on Chicago’s beaches compared to 2007. The reduction in the number of gulls using Chicago beaches has contributed to a reduction in conflicts with gulls, including a decrease in the frequency of swim advisories/bans on Chicago’s beaches in comparison to 2006.

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