A 2.5 km movement by a potentially ill white-tailed deer along Nantasket Beach in suburban Massachusetts, USA

White-tailed deer (Odocoileus virginianus) ecology has received significant research attention, yet there is a need for further synthetic work on the species across environmental contexts and research areas. Opportunistic natural history accounts can help identify new conceptual links and research directions by offering new observations and ideas, synthesizing context from the literature, and highlighting gaps in understanding. We provide an opportunistic account of a 2.5 km movement of a white-tailed deer walking, wading, and swimming along Nantasket Beach in a suburban context in Massachusetts, USA. The deer displayed behaviors that could potentially be reflective of trauma, disorientation, or illness, including possibly symptomatic head movements and crouching behavior. The behavior of the deer may also have been influenced by the coastal and suburban context in which the observation took place. Our account explores swimming, deer behavior, and possible illness in a coastal, suburban context. We highlight the need for additional research on the ecology and management of white-tailed deer, including swimming and disease in coastal, marine, and developed contexts, and intersections across these areas.