AbstractWe examined the influence of two habitats, old field and small islands on a river, on the propagation of amplitude and frequency characteristics of song sparrow songs.At 27 m from the source, songs originally recorded in the field degraded significantly less there than over water in the river. At that distance, songs recorded on the river also degraded less in the field than over water, but the differences were not significant. At 54 m from the source, songs recorded at both sites also tended to degrade more on the river than in the field, but the differences were not significant. Songs from the two habitats differed significantly in the total number of amplitude peaks in a song, in song duration, in maximum frequency, and frequency range. They did not differ significantly in the fraction of peaks in the upper amplitude range, and in the width of the amplitude range.The results suggest that, in fields, a more typical habitat, songs are locally adapted to communication at about 30 m but poorly so at 60 m from the source. We suggest that this is related to the territory size of birds in the field. The results are discussed in relation to the ranging hypothesis (Morton 1982) that predicts that the least degraded song types would be selected for, and that listeners use degradation to estimate their distance from singers.