| Abstract |
- Studies of anthropogenic impacts on wildlife may produce inconclusive or biased results if they
fail to account for natural sources of variation in breeding performance and do not use probabilistic sampling
at a scale functional for management. We used stratified random sampling and generalized linear mixed
models to test hypotheses on relationships of daily nest survival rate (DSR) and fledgling production with
anthropogenic and environmental factors that influence reproduction in the ferruginous hawk (Buteo regalis).
We conducted the study across ferruginous hawk range in Wyoming, USA, 2010–2012. We performed
extensive field surveys of prey, vegetation, and nest substrates, and used spatially explicit data to quantify
weather, and the most widespread forms of anthropogenic infrastructure (i.e., roads, oil and gas well pads) in
ferruginous hawk territories. We found strong evidence that DSR and productivity were greater for nests on
anthropogenic structures (i.e., artificial nest platforms, gas condensation tanks, abandoned windmill
platforms, power poles) compared to natural substrates (i.e., trees, cliffs, rock outcrops). Additionally,
ferruginous hawks produced more fledglings at territories with greater shrub cover and fewer severe storms
during the June brood-rearing period. Amount of oil and gas development and prey was not associated with
either measure of breeding performance. Our results suggest that artificial nest platforms are an effective tool
to improve breeding success of ferruginous hawks and nesting on anthropogenic structures does not
constitute an ecological trap for this species. Although ferruginous hawks nested in some areas with very little
vegetative cover, territories with greater amounts of shrub cover produced more fledglings. The negative
impact of severe spring storms on fledgling production illustrates the importance of including future weather
scenarios in management planning for this species because storms are predicted to increase in frequency and
intensity as a result of climate change.
- Keywords: prey abundance, oil and gas development, fledgling production, Buteo regalis, anthropogenic infrastructure, ferruginous hawk, nest survival, severe weather, Wyoming, artificial nest platform
- Keywords: prey abundance, oil and gas development, fledgling production, Buteo regalis, anthropogenic infrastructure, ferruginous hawk, nest survival, severe weather, Wyoming, artificial nest platform
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