three years of monitoring, that's why. >> reporter: smallwood says when the alta mont was first built, wind energy companies installed over 7,000 turbines, more than twice as many as there are today. they gave little consideration to bird safety. >> those are the most dangerous turbines in the alta mont pass on record. 1 one is on record having killed one eagle per year for ten years. there's a lot of eagle traffic through the alta mont pass. >> reporter: the birds fly lower in some areas to avoid wind resistance and to hunt for ground squirrels. golden eagles have keen eyesight which is good for hunting prey but it doesn't help the birds detect wind turbines. especially when they're focused on other things. >> social interactions are very important. so an eagle responding to other eagles, chase each other around, chasing some other buries. these are dangerous social interactions that lead up to what we call events, near-misses. >> reporter: the federal government has recently stepped up enforcement of laws aimed at protecting golden eagles. it's prosecuted two wind companies whose tu

increases its wind power capability, scientists, including shawn smallwood, believe fewer turbines andlacement are key to protecting wildlife. >> we've learned a lot here. so it should be the number one laboratory in the country for learning what not to do wrong with wind development around the rest of the country. >> reporter: for the pbs newshour, i'm scott shafer. >> woodruff: it's been a busy week in the political world. hillary clinton testified during a marathon benghazi committee hearing; paul ryan says yes to run for speaker of the house; and republican ben carson surpassed donald trump in the polls in iowa. for more we turn to the analysis of shields and brooks. that's syndicated columnist mark shields and "new york times" columnist david brooks. welcome, gentlemen. so, benghazi hearings, david, it was eight or nine hours of testimony. what if we learned? what was accomplished at this hearing? >> nothing was learned. we learned the republicans can't stump hillary clinton. she was composed, gave a lot of the same testimony she's given before, this thing has been going on foreve