This image towards the bottom
http://www.speakerfactory.net/wbuoy2.jpg

Birds avoid 'em and they're prettier, I think, than those propeller-blade things.

Go to google and put in this phrase in the search bar:

Wind turbines and birds

You will have reports to read for days and days!  The problem is, the results are somewhat inconclusive.  From my reading (and I have made my eyes hurt reading the subject, since I am involved in an experimental wind turbine firm)
the main consensus looks like this:

a.  Wind turbines do sometimes kill birds.
b.  Location means everything.  If the turbines are located in a flyway of large predatory birds, the damage can be severe.  If the birds are already endangered species or a population small in number, it becomes a serious issue to confront.
c.  In areas not frequented by larger predatory birds such as hawks, owls, eagles, the damage is less severe, and probably no worse than any other tall structure such as cell phone towers, guy cables to cell and broadcasting towers, taller glass buildings, and fossil fuel towers, etc.  Birds do also strike those.  Let us not forget the killing of birds by aircraft.
d.  It is the spinning motion of the blade that makes wind turbines more dangerous to birds.   They never know what hit them.  However, some studies do indicate behavior change by the birds over time.  The sight/smell of dead birds on the ground make the living ones leery to go there (this is not a joke, birds do "learn".  Experiments have also been done with colered ribbon, noise makers, etc., to dissuade birds from going near wind turbines.  The results are still inconclusive in most cases.
e.  The issue of perception is crucial.  Since wind is percieved by it's supporters as "environmentally friendly" power, any bird kill by wind turbines will be viewed much more seriously than the same kill would be viewed if it were caused by a fossil fuel plant.  Thus, the Audoban Society, Seirra Club, National Wildlife Fund, etc.,  have shown great interest and made intensive studies of the bird kill issue, and the wind industry is always working to address it.  
f.  Regarding the above, almost no such scrutiny concerning bird kill has ever been placed on the fossil fuel industry.  Open waste storage tanks are deadly to birds, and the "catch basin", "retention ponds" and lagoons for oil and coal "tailings" of many oil/coal drilling/processiong operations can contain hundreds, sometimes thousands of dead birds.
g.  Other industries and agriculture can be deadly to birds.  One of the great killers of predatory eagles and hawks is the fence, be it barbed wire or woven wire.  When a predatory bird spots prey, their eyes focus to that prey, and the fence between them and the prey become invisible to them.  I know that in Kentucky and Indiana, several eagles have been rescued from fences with broken wings.

In closing, wind power is expected to act to a higher standard than the fossil fuel industry, and rightfully so.  Any developing technology reducing danger to birds, should and I think will be implemented.

Roger Conner  known to you as ThatsItImout

In addition to ThatsItImOut's points, it's worth mentioning that the newer, bigger turbines with larger, slower-spinning blades are much easier for birds to avoid and pose less of a danger than the models of 20-30 years ago.