This is Bird Note. In 2014 on the Olympic Peninsula in Washington State, the dams on the

L.W. river were removed, was the largest removal of its kind in history. As the river ran

free again, salmon from the Pacific were able to spawn upstream for the first time in 100

years, having a dramatic impact on American dippers, lively little riverside birds.

Biologists with the lower L.W. clalom tribe, the Smithsonian Migratory Bird Center and Ohio State

University drew small samples of blood from dippers that they then released unharmed.

Analysis of blood and feathers showed that birds with access to salmon have higher survival rates,

and the females have better body condition than those with no access to the fish.

These dippers are also much more likely to stay on their home territories,

rather than expend energy to forage widely. And there are 20 times more likely to attempt

raising two broods in a season, the most important contributor to population growth.

So nutrients from spawned out salmon and salmon eggs are giving the river's ecosystem new vitality.

For Bird Note, I'm Mary McCann. Bird Note gives you the sounds of birds every day,

and you get the sights as well when you follow us on Instagram at Bird Note Radio.