Today's San Francisco Sparrows Sing At Higher Pitch
White-crowned sparrows sang at a lower pitch in 1969 than in 2005. These sonograms of the San Francisco dialect show a big change in frequency — like going from 'Do' to somewhere between 'Fa' and 'Sol' in a solfège music lesson. Press the 'play' buttons and listen carefully for the change. Source: Elizabeth Derryberry and David Luther.