A lone American Dipper was at Bridge 2 , likely the male, standing on the rocks right below the bridge. A few short bouts of singing were heard. No active nest building and no sign of the other pair member. Another bird did come into Bridge 2 territory and a territorial scuffle commenced. After some chasing and loud calling the intruder flew upstream with the Bridge 2 bird in pursuit. After about 5 minutes the Bridge 2 bird returned to his vigil. Some question remains about the fate of the female as a peek under the bridge revealed only the beginnings of the moss dome.