Birds and humans appear to have agreed to disagree about the merit of a $1.5 million Lake Merced revamp, which involved clearing tule stands and building a fishing pier and picnic area at the south end of the lake. That corner of the lake is perennially packed with a variety of migratory and native freshwater birds, including gulls, coots, mallard and ruddy ducks, cinnamon teal, gadwalls, buffleheads, canvasbacks, lesser scaup, cormorants, terns, ospreys, and swallows. The expensive human facilities, however, tend to be barely used, making for an uninterrupted pageant of courting, fighting, scavenging, diving birds.