Traffic noise permanently raises song tonality in red-winged blackbirds

Evidence

Noise from anthropogenic origin seems to produce permanent changes in the structure of song in red-winged blackbirds (Agelaius phoeniceus). In fact, population living in quiet marshes far from traffic noise, when exposed to traffic noise playback reacted with an increase of signal tonality, demonstrating high acoustic plasticity (Hanna et al. 2011). But in marshes located at the side of traffic-heavy roads, red-winged blackbirds maintain higher tonalities when the area is temporarily not exposed to traffic noise. This last fact demonstrates that anthropogenic noise influences the structure of their song, at least in this species. — Almo Farina, Soundscape Ecology, 1384

Categorization

• QUESTION: Is the persistent high tonality in noise-exposed birds a maintained learned adaptation, or does it indicate a changed perceptual template carried into otherwise quiet moments?
• XREF: connects to: Species shift calls to ultrasonic frequencies to escape constant noise masking — Almo Farina, Soundscape Ecology: Principles,…, 1288; Bill size modulates avian song frequency and trill rate — Almo Farina, Soundscape Ecology: Principles,…, 400; Tropical nighttime noise of 60-65 dB disrupts katydid mating entrainment — Almo Farina, Soundscape Ecology: Principles,…, 1291 (+4 more)

Broader Connections

• Urban birds shift their songs to higher pitches to escape traffic noise #exemplifies (0.88) — Gordon Hempton, John Grossmann, One Square Inch of Silence- One Man’s…, 941
• High-pitched bird species tolerate roadside noise better than low-pitched ones #expands (0.82) — Almo Farina, Soundscape Ecology, 1383