Previous studies have shown negative associations between wind energy development and breeding birds, including species of conservation concern. However, the magnitude and causes of such associations remain uncertain, pending detailed ‘before-after-control-intervention’ (BACI) studies. We conducted one of the most detailed such studies to date, assessing the impacts of terrestrial wind energy development on the European Golden Plover Pluvialis apricaria, a species with enhanced protection under European environmental law. Disturbance activity during construction had no significant effect on Golden Plover breeding abundance or distribution. In contrast, once turbines were erected, Golden Plover abundance was significantly reduced within the wind farm (−79%) relative to the baseline, with no comparable changes in buffer or control areas. Golden Plovers were significantly displaced by up to 400 m from turbines during operation. Hatching and fledging success were not affected by proximity to turbine locations either during construction or operation. The marked decline in abundance within the wind farm during operation but not construction, together with the lack of evidence for changes in breeding success or habitat, strongly suggests the displacement of breeding adults through behavioural avoidance of turbines, rather than a response to disturbance alone. It is of critical importance that wind farms are appropriately sited to prevent negative wildlife impacts. We demonstrate the importance of detailed BACI designs for quantifying the impacts on birds, and recommend wider application of such studies to improve the evidence base surrounding wind farm impacts on birds.