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dentremont@hotmai Hi All, We've discussed wind turbines a number of times on NatureNS in the past and I'm sure that Dave Webster will be able to supply information from his comprehensive archive of NatureNS material. The long and the short from my perspective is that the engineering of wind turbines has greatly improved since they appeared in the now infamous Altamont Pass (This is the location where there was/is a large raptor migration and which resulted in a large mortality of birds) and bird mortality at most sites is apparently negligible. Much of the mortality was due to transmission lines and supporting structures. The lines are now underground and the towers are free standing. This is in respect to bird mortality. Bat mortality is something entirely different, most of it due to the rotating blades. However, location can be critical and some radar studies I've heard of show that a few hundred meters can make a big difference in many locations. As I've said in past emails, there is really no excuse in many cases that turbines are not located in low risk as opposed to high risk sites but many conflicts still arise as high risk sites are targeted. For example, most birds migrate at heights above tower height however, there are key areas where migrants are known to descend to ground level. Putting a turbine farm at these spots would be ill advised. Lastly, the last time I looked at the guidelines for conducting bird inventories at potential sites they appeared to be inadequate. Determining whether there was a risk to migrating birds by censusing a site 2-3 times during the fall migrating period just doesn't cut it. That was a while ago so perhaps they've now been improved. All the best, Lance Lance Laviolette Glen Robertson, Ontario
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