Birdsongs keep pace with city life: changes in song over time in an urban songbird affects communication

► We evaluated effects of urban noise on structure and salience of white-crowned sparrow song over a 36-year period. ► Birdsong increased in minimum frequency between 1969 and 2005 coincident with rising levels of traffic noise. ► Birds in urban environments gave stronger responses to current songs than to historical songs. ► Results support the hypothesis of habitat-dependent selection on cultural evolution of birdsong in urban environments.