Steep-walled catchments are a source of wildlife mortality. Incidental to searching for carcasses under five wind turbines in the panhandle of Texas, we discovered vertebrate carcasses on a frequent basis in concrete oil-catchment basins associated with each turbine's transformer. During 2015 and 2016, we found remains of 62 vertebrates trapped in these basins. We recommend new designs that prevent entrapment and addition of escape ramps to existing basins to reduce the frequency of trapped animals. Mitigation of mortality of the level that we observed could significantly reduce this unnecessary impact on wildlife from what is a far-reaching and growing industry.