Overall, the parameters estimated by our model agree with previous knowledge about the Black Harrier, which reinforces our confidence both in our predictions and in our understanding of the ecology of the species. The model estimates a survival rate for adult Black Harrier around 0.7 and for fledglings of about 0.5. These numbers are similar to those estimated for other harrier species \citep{Newton_2016,Arroyo_2002}. Mean fecundity per breeding pair is estimated to be 1.5 fledglings, which also similar although somewhat lower the 1.9 previously observed by \citet{Curtis2004} and slightly less than the 1.65 reported by \cite{Garcia_Heras_2017}. We feel this decrease may arise because of the close link that is emerging between harrier fecundity and rainfall uncovered by \cite{Garcia_Heras_2017} and confirmed here. As rainfall declines in the core breeding areas of the Western Cape \cite{abrahams} so we would expect harrier fecundity to decline still further in future. Slightly lower fecundity could also be capturing the fact that we assume in our model that all adult breeding pairs do, at least, attempt to breed, which might no be realistic, and some pairs may take sabbatical years.