During the COVID-19 pandemic, Rottnest Island, Western Australia, a popular tourist destination, was closed to the public for 72 days (from 25 March 2020 to 5 June), so that it could be used as a quarantine facility. Silver Gulls Larus novaehollandiae were surveyed in the main settlement area over 429 days, beginning at the commencement of the quarantine period, with a focus on a previously identified problem area, the shopping mall. These surveys allowed for the comparison of Silver Gull numbers with and without the presence of easily accessible anthropogenic food. The number of Gulls was extremely low during the quarantine period, followed by a 578% increase in the same period the following year when visitors returned. During the period of food scarcity, many of the Gulls appeared to have left the Island, which suggests that the number of pest birds on Rottnest Island can be influenced by the amount of anthropogenic food available to them.