Saving energy… and golden eagles

>>> as we all head into another air-conditioned summer weekend, we have a story tonight about a man who is trying to make sure an important source of alternative energy , windmills can co-exist with one of this country's most loved and majestic birds. here's nbc's chief environmental continue anne thompson .

>> reporter: east of san francisco , 35 miles an hour are ideal for wind turbines and golden eagles . for self-years these majestic protected birds and this power source have led an uneasy co-existence.

>> i would rate wind farms as one of the highest dangers of golden eagles .

>> reporter: 50 to 70 of the birds are killed each year by turbines, he says, today there are not enough eagles left to produce young birds to replace those lost. so this is basically a numbers game?

>> yes.

>> and the way it's set up now, golden eagles are losing?

>> s that correct. as a park district , we're very concerned.

>> so is the u.s. fish and wildlife service , it's creating national, voluntary guidelines for wind farms , to protect the eagles from injuries that the doctor sees.

>> even if it doesn't kill them, it makes it so they can't fly ever again. pattern energy says the new taller turbines are better for the birds and man.

>> today's technology allows us to be much more efficient in capturing the wind.

>> so fewer turbines are needed, 38 new ones replace 174 old turbines.

>> one study shows bird deaths here have dropped by a dramatic 80%. and golden eagle deaths have been halved. but technology is just one part of the solution. another doug bell is keeping turbines away from eagles flight pattern.

>> eagles don't fly randomly around the area.

>> reporter: finding a better way for man and eagles to benefit from the power of the wind . anne thompson , nbc news, altimont pass, california.