Searching only roads and pads is a convenient way to survey for carcasses, but the critical question is how reliably total mortality can be estimated from these data. Researchers considered five methods to estimate the proportion of carcasses falling within searched boundaries on only, or primarily, roads and pads. They simulated spatial distributions of carcasses and the search process under a range of conditions and evaluated the statistical properties of these methods. Authors suggest a semiparametric bootstrap to estimate the proportion, and associated uncertainty, of carcasses that land in the searched area. Under some conditions, accurate and precise mortality estimates can be generated from data collected entirely on roads and pads, but small observed counts or patterns in directional distribution of carcasses relative to road or pad construction may compromise estimates.  

Maurer, J.D., Huso, M.M., Dalthorp, D.H., Madsen, L., Fuentes, C., 2020, Comparing methods to estimate the proportion of turbine-induced bird and bat mortality in the search area under a road and pad search protocol: Environmental and Ecological Statistics, https://doi.org/10.1007/s10651-020-00466-0