There are at least two conceivable ways to incorporate additional mortality produced by wind farms. The first one considers a constant extraction of birds every year, which means that the change in survival rate varies each year. This is because the ratio extraction-to-population changes as the population fluctuates. Alternatively, we may consider a fixed change in (expected) survival rate induced by the interaction with wind farms. Under this premise there is a density-dependent mortality, by which the number of harriers dying at wind farms is proportional to the harrier population. While a density-dependent mortality might be more realistic, we consider a constant extraction scenario to be more illustrative for management purposes, and therefore, we adopt this approach. In addition, very little is known about density dependence in harrier species' population parameters \citep{e2000}.