Male Java sparrows (Lonchura oryzivora) produce bill-click sounds along with their songs during courtship displays as well as when they sing to themselves when alone, has found a team of ornithologists at Hokkaido University, Japan.
An adult Java sparrow (Lonchura oryzivora) in Honolulu, Hawaii. Image credit: Kim Bridges / CC BY 3.0.
Birds may communicate using both vocalizations and movement, as for instance occurs during courtship displays, but scientists’ understanding of how they coordinate their movements with the sounds they produce is limited.
To further investigate birds’ communicative and musical abilities, Dr Masayo Soma and Dr Chihiro Mori of the Hokkaido University’s Department of Biology looked into the vocalizations and bill sounds associated with singing in the Java sparrow.
Specifically, they investigated differences in bill-click frequency, coordination between song notes and bill clicks, and learnability of bill-click by analyzing recordings of undirected songs made by 30 domesticated male Java sparrows.
The ornithologists observed male Java sparrows coordinated their bill-click sounds with the notes of the song, similar to percussionists.
They also observed birds producing clicks frequently toward the beginning of songs and around specific song notes.
Related birds showed similar bill-clicking patterns, but the scientists also observed that birds never exposed to clicking sounds also clicked their bills.
“There may be some learnability in the bill clicking that is learned, but that it may be an intrinsic behavior,” said Dr Soma and Dr Mori, authors of the paper discussing the results in the journal PLoS ONE.
“The bill-clicking sounds may be integrated with vocal courtship signals in a songbird, but further research is needed to understand the role bird vocal and movement communication plays.”
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Soma M. & Mori C. 2015. The Songbird as a Percussionist: Syntactic Rules for Non-Vocal Sound and Song Production in Java Sparrows. PLoS ONE 10 (5): e0124876; doi: 10.1371/journal.pone.0124876
