It’s often said that a rock band is only as good as its drummer. The Java Sparrow, a popular pet bird indigenous to Indonesia, couldn’t agree more.
In a paper published in PLOS ONE, Japanese researchers Masayo Soma and Chihiro Mori determined that male Java Sparrows click their bills in tune with their songs, the same way that a human percussionist would lay down the beat for a vocalist.
The video above, taken by the researchers, shows a male and female producing sounds with a slight grinding movement of their bills, as well as by banging their bills on their perches. Dancing and singing follow, along with more bill clicking. They then top their performance off by copulating.
The bill clicks aren't just being produced at random; they're synchronized with the birds’ calls. The researchers realized this by examining recordings from 30 domesticated male Java Sparrows. It turns out that bill clicks are more common toward the beginning of songs and around specific song notes.
Bill clicking is probably also intrinsic: During the experiment, eight young Java Sparrows were raised in a click-free environment and were still able to produce the sound. There are likely some learned elements, however, since bill-clicking patterns were notably similar between fathers and sons.
Though research on the topic is relatively scarce, other creatures have been found to synchronize sounds with other sounds or with their own movements. A 2004 study published in Science, for instance, showed that male Brown-headed Cowbirds perform their most elaborate wing displays during gaps in their courtship song.
Soma and Mori write in the paper: "Investigating how animals coordinate their movements with the sounds they produce holds the key to understanding the evolution of communicative and musical cognitive abilities.”