Abstract—The output power from a stationary PV module tends to fluctuate throughout a day. This may be due to shading caused by clouds, contrails, trees, buildings and birds. The purpose of this paper is to quantify the impact of one pigeon dropping on the output power of a 10 W PV module that is located in a semi-arid region of South Africa. Data used in this experimental quantitative study was obtained from a LabVIEW software program that was designed to monitor and record the output power of a number of identical PV modules. Observations from this data enabled photographs to be taken of the PV modules that highlight the pigeon dropping. Results indicate that the instantaneous output power of these 10 W PV modules may be reduced by up to 5%, depending on the location of the single dropping. If the dropping is not removed, then a 1.5% power reduction can be realized for an entire day. A recommendation is to regularly clean these modules in areas that are well inhabited by pigeons, as every accumulated loss of power may lead to system downtime or even component failure over a period of time.