Thus, our aim here is two-fold: i) to investigate the use of dynamic occupancy models to study the viability of populations of species affected by wind farm development for which only presence/absence data, and no population counts, are available, and ii) study the viability of the Endangered Black Harrier, who's restricted breeding range is being rapidly populated with wind farms in South Africa.
Methods
Black Harrier breeding and wind farm monitoring
Black Harrier breeding and movement data were gathered over 18 years throughout South Africa with an emphasis on the core breeding areas in south-western Cape \citep{Curtis2004,Garcia_Heras_2017}. Breeding success was monitored in a series of studies starting in 2000 with a focus on productivity in the two main habitats: west coast regions, where the principal small mammal prey are numerous, and montane areas inland, where prey are more varied, breeding seasons are shorter and breeding success lower than at the coast \citep{Garcia_Heras_2017,Garcia_Heras_2016}. Intensive data collection finished in 2017, spanning 18 years for breeding studies. Data on adult survival were derived from adult birds wearing PTT or GSM-GPS tags to follow their movements from 2008 to 2015. Details and methodologies of the monitoring protocols for the breeding studies \citep{Garcia_Heras_2017} and satellite tracking studies \citep{2019} are given elsewhere.
A more focused four-year study of Black Harriers using and breeding within an operational wind farm in the Eastern Cape ( S34° 00'49" and E24°50' 50") added to our understanding of the behaviour of birds in and around turbines. That observational study (RE Simmons, M Martins, unpublished data) took place from 2016 to 2019 at the 60-turbine Jeffreys Bay wind farm, and focused on the use of space, flight heights and breeding success of the nests found within the wind farm boundaries. Simultaneous and systematic carcass searching by Inkululeko Wildlife Services of all turbines over a two-week interval allowed us to relate harrier flight activity and turbine identity to raptor deaths.
Population dynamics model and simulations