Bird guano accumulated on solar photovoltaic (SPV) panels caused a reduction of its output power by blocking the sunlight received on it. Therefore, thermal imaging was used to understand and study the effect of bird droppings accumulated on SPV panels. Four number of bird droppings (1, 2, 3, and 4 drops) were studied and compared with clean SPV panel (control). Front and backside temperatures of the SPV module have been evaluated in addition to current, voltage, power, and e ciency of the SPV modules. The study found that high-density of droppings accumulation on the frontside of SPV modules signi cantly decreased their temperature due to increased solar radiation re ection. The bird guano accumulated on the SPV module with 4 drops led to a decrease in output currents of the SPV modules by 36-38% as compared with the clean SPV module. While the module voltage was found to be slightly affected by the bird guano accumulated on it. The bird guano accumulated on the SPV module with 4 drops led to a decrease in output power and e ciency of the SPV modules by 26% and 43% respectively as compared with the clean SPV module. Therefore, the importance of this work is to understand how the accumulation of feces affects the performance of the SPV performance, as it clearly demonstrates its negative impact.