Unfortunately, it is economically not viable to turn off the turbines during
the several weeks of migration, twice a year. There have been suggestions
that real-time radar information be used to turn them off (actually, the
term is "feather" believe it or not - they rotate so that the blades are
parallel to the wind and won't turn) during the parts of the nights when
flocks are coming through. Even that could be problematic, though, for two
reasons. One is an inherent drawback of wind energy - it isn't constant. If
the wind doesn't blow - no wind, no wind energy. If the wind blows too hard
- no energy, because the blades have to be feathered to avoid damage. So
feathering the turbines due to the presence of birds will simply exacerbate
this problem. Second, the altitude of migration may be such that feathering
is not necessary, but as I understand it, the NEXRAD radar that is used to
detect the movement across space does not detect altitude of flight. Mobile
marine (ground-based) radar has been used for this purpose, but then of
course, you'd have to be sure that you have these units all over the place,
and someone monitoring them in real-time. 



Ellen Paul
Chevy Chase, MD 20815