Fig 3. Song minimum frequency is related to background noise levels across all sites.
Song minimum frequency is on the y-axis and the amplitude of background noise is on the x-axis. Urban locations included the San Francisco dialect sampled at UBattery East, UInspiration Point, and ULobos Dunes and the ULake Merced dialect sampled at Lake Merced. See text for dialects at rural locations including RCommonweal, RAbbott's Lagoon, RLighthouse, RSchooner Bay, RSouth Beach, RMcClures Beach, and RLimantour. The solid line represents model average predictions and the dashed line represents the standard error.