Behaviour 2019
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Females sing louder than males in duets of a Neotropical bird
Pedro Diniz, Edvaldo Silva-Jr, Fernando Almeida, Pietra Guimarães, Renato Oliveira, Regina Macedo. Universidade de Brasília, Brasília, DF, Brazil

The amplitude of acoustic signals influences their transmission efficiency through the environment. Individuals may overlap acoustic elements to improve the propagation of duets or choruses. For instance, partners may benefit from overlapping acoustic elements to announce territory possession to farther neighbors. However, it is unknown if song amplitude differs between duetting partners and if signal overlapping increases the amplitude of duets. We addressed these questions in the Rufous Hornero (Furnarius rufus), a bird where partners partially overlap their duet phrases in frequency and time. We compared the relative amplitude of non-overlapped female syllables, non-overlapped male syllables, and overlapped female-male syllables in duets produced when partners were close to each other (< 3m). Females produced higher amplitude (non-overlapped) syllables than males. Overlapped female-male syllables had higher amplitude than non-overlapped syllables. These results suggest that female phrases are louder and can propagate farther than male phrases and that partners may benefit from increasing syllable overlapping to enhance duet propagation.