Reverberation favors low-frequency slow trills over fast high-frequency ones for long-range communication

Evidence

Experiments conducted by Naguib (2003) have demonstrated that fast trills transmit less well than slow trills, with effects on long-range communication. In Fig. 3.8 and in Fig. 3.9 is shown how reverberation increases with increasing vegetation cover and in relationship with the frequency of the trill element. Low-frequency notes slowly repeated are less affected by reverberation and can assure long-range communication better than high-frequency notes quickly repeated, as has been observed in birds living in open and densely vegetated habitats. — Almo Farina, Soundscape Ecology, 443

Categorization

• XREF: Extends the earlier ch8 claims (whistles beat trills in closed habitats; excess attenuation rises with frequency in vegetation) into the mechanism: reverberation penalizes fast trills. — connects to: Excess attenuation increases with frequency in vegetated habitats — Almo Farina, Soundscape Ecology: Principles,…, 418; Vocal transmission distance depends more on singing height than frequency — Almo Farina, Soundscape Ecology: Principles,…, 424; Whistles beat trills in closed habitats while trills beat whistles in open ones — Almo Farina, Soundscape Ecology: Principles,…, 425 (+1 more)

Broader Connections

• Pure-tone notes exploit reverberation to travel farther in dense forest #corroborates (0.72) — Almo Farina, Soundscape Ecology, 432