Birds, Bats and Turbines
With the expansion of the wind industry, some wildlife advocacy groups worry that these tall structures will lead to increased bird and bat deaths due to collisions with the blades.
Some ornithologists and biologists also speculate that the presence of turbines in prairie regions, wetlands or coastal staging areas for migratory birds may lead to habitat destruction. (Staging areas are where migratory birds rest and re-fuel during long journeys.) Birds of prey, whose smaller numbers are more greatly impacted by turbine-related fatalities, present another concern to wildlife biologists.
Green energy experts point out that birds and bats collide with all large manmade structures. In fact, in recent years, refinements in turbine design appear to have reduced bird deaths, with fewer carcasses found at the base of the towers. At the same time, the risk of collision may grow with larger turbines due to an increase in blade size or tip speed.
The bats and energy wind cooperative (BWEC) has launched several projects to determine the effect of varying the cut-in speeds of turbines on bat fatalities . Research has suggested that halting turbines during periods of low wind speeds, when bats are most active, may reduce the risk of bat fatalities at minimal economic impact . Such measures may also alleviate the impacts of barotrauma, or damage to an animal's respiratory system due to the sudden drop in air pressure created by rotating wind turbines.
In Canada, one important means of protecting habits close to wind farms involves oversight by the Canadian Wildlife Service. Wind farms in Canada are eligible for federal grants, and are therefore subject to federal environmental assessment rules. When a new project comes forward, the CWS will be able to assess whether the proposed sites are too close to wetlands and other habitats.
This animated slideshow is a step-by-step guide to making a working model of an anenometer (a device that measures wind speed) from common household items such as cups and a pencil. Images, animations and text guide the user through each step in detail.