Thermal image movie of flying animals passing in vicinity of wind turbine
(click to see & hear 4 minute movie; ~75 MB)
This thermal image movie was made with a FLIR P640 camera at ~12:30AM on September 29, 2008 at wind turbine #134 on the northwest side of the Maple Ridge Wind Project near Lowville, NY. This location is on the extreme northern edge of the Tug Hill Plateau and terrain to the north is at lower altitude for more than 100 km. A significant bird migration, as evident from flight calling, had begun by 11PM on September 28. Birds that had started their southbound migration from further north were now encountering the high terrain of the Tug Hill Plateau. They are seen in movie passing by at low altitude (estimated 50-100 m agl) under a low cloud ceiling that periodically during the night was at ground level. The evening had northerly winds, fog, and occassional light rain. The temperature was in the low 50s F. The camera was mounted on a tripod about 100 meters northwest of the wind turbine -- a 1.5 MW model with a tower 80 meters above ground level (agl) and a rotor diamter of ~82 meters.
This 4 minute video shows about 30 targets that are believed to be mostly migratory songbirds. More than 60 passerine (songbird) flight calls are indicated on the accompanying soundtrack. These flight calls indicate Gray-cheeked and Swainson's Thrush, Black-throated Blue, Parula, and Magnolia Warbler, and Lincoln's Sparrow among others. Most of the presumed bird targets are moving from right to left across the image. This corresponds roughly to a northwest to southeast or west to east flight path. Some individuals appear to deviate their flight direction and circle about upon encountering the wind turbine.
The acoustic station at wind turbine #134 recorded over 300 warbler and sparrow flight calls in four hours (from 10PM-2AM) on this evening. This was amidst noise from the wind turbine. A second acoustic monitoring station approximately 10 km to the southeast and 90 m higher altitude than the WTG #134 acoustic station recorded only 91 warbler and sparrow flight calls during an 11 hour period this evening. A third acoustic station operating on the Cape Vincent Peninsula (~58 km to the northwest & 250+ m lower altitude than the WTG #134 acoustic station) recorded over 1300 warbler and sparrow flight calls in 10 hours. These data suggest that there was a heavy low altitude flight of warblers and sparrows across the region this evening. The flight call data suggests that this high density flight was not passing over the Tug Hill Plateau and was perhaps generally staying under the low cloud ceiling and only skirting the lower edges of the northern portion of the Plateau. If this is so, the high passage rates documented in the thermal movie and indicated the wind turbine #34 acoustic data may only have intercepted a few of the lower altitude wind turbines at the northern reaches of the wind project.