Clinical Assessment and Outcomes of Wildlife Rescued during Reservoir Filling of a Small Hydropower Plant in Paraná, Brazil

Reservoir filling for small hydropower plants (SHPs) leads to rapid environmental changes that directly affect wildlife, increasing the demand for rescue and clinical intervention. This study aimed to describe the clinical assessment and management of wild animals rescued from the water, adrift during the filling of an SHP reservoir in the state of Paraná, Brazil, emphasizing species distribution, clinical findings, and outcomes. Rescues were conducted using a support boat, and animals were transported to a field station for triage and evaluation. A total of 100 animals were examined, including reptiles from the families Colubridae, Gekkonidae, and Amphisbaenidae, and one bird from the family Hirundinidae. Clinical evaluation included palpation of the coelomic cavity and spine, body condition scoring, inspection for injuries, assessment of mucous membranes and cloaca, and measurement of respiratory rate and, when feasible, heart rate (via Doppler in reptiles and auscultation in the avian patient). Neurological assessment in reptiles was based on the righting reflex. In the bird, it included posture, balance, and response to stimuli. The avian patient required tranquilization due to dyspnea during handling. Among the rescued animals, reptiles accounted for 99% of cases, with a predominance of amphisbaenians, particularly Leposternon microcephalum (69%) and Amphisbaena cf. mertensii (26%), while Leptotyphlops sp., Oxyrrhopus guibei, Erythrolamprus poecilogyrus, and Hemidactylus mabouia each represented 1% of cases. The only avian species recorded was Pygochelidon cyanoleuca. Most animals were in good clinical condition, with no severe abnormalities, and the righting reflex was preserved in the majority of reptiles, indicating adequate neurological function. Thermal support using heating pads was essential for stabilization, especially in reptiles presenting lethargy or hypothermia. All animals showed favorable recovery and were successfully released. These findings highlight the effectiveness of immediate clinical assessment and supportive care in wildlife rescue operations and reinforce the importance of standardized protocols in mitigating the impacts of environmental disturbances.