Factors influencing avian movement patterns around proposed ridgeline wind farm sites in British Columbia, Canada.

Due to the concerns over global warming, the demand for green renewable energy is escalating. Wind farms in Canada are being approved for construction at an exponential rate. Because large scale wind energy is relatively new technology, concerns have surfaced over the impact of wind turbines on aerial fauna, such as birds and bats. Proper monitoring protocols designed to understand the animals' behaviour around these structures are thus vital to identify potential risks. I monitored bird migration at three mountain ridges near Chetwynd, British Columbia. By using a combination of radar to track nocturnal migrants and stand watches to track diurnal migrants, I investigated how birds use landscape features during migration and how these movement patterns are influenced by regional weather systems. I found evidence that raptor movement patterns were influenced by topography, as diurnally-migrating raptors tend to move in concentration parallel to the windward edge of the ridgelines. Conversely, nocturnal movement patterns appeared less influenced by local topography than diurnal migrants. After collecting weather data and examining their effect on avian passage rates, I found that a combination of barometric pressure, cloud cover and wind speed was generally best able to explain and predict passage rates (wind speed being a strong variable). By understanding the spatial and temporal patterns of migration, wind farm proponents can develop mitigation strategies to minimize collision risk.