A study by the Hokkaido University revealed that a pas de deux or a dance duet is a prelude to the mating of Java sparrows, scientifically known as "Lonchura oryzivora". This contradicted the earlier belief that the primary sexual signal for the birds is singing. The sparrow is a breeding bird found in Indonesia particularly in Bawean, Bali, and Java, but now in other countries as well. These particular sparrow species are cage birds that can live up to three years.

Researchers, who studied the behavior of the Java sparrows, found out that while singing is a prelude to mating, this was only done by the male sparrow after a copulation solicitation display (CSD) is made by the female bird, as per Neuro Science News. Singing appeared to be done only for courtship to attract the female's attention. Duet dancing is, however, a mating signal for both the male and female birds.

The study on the Java sparrows was conducted by Hokkaido Associate Professor Masayo Soma and Midori Iwama and was published in the PLoS ONE journal. The researchers found out that the duet-dancing played a more important role in determining the success of the mating process than singing which only served as a signal of readiness to mate. Either the male or the female sparrow could initiate the duet-dancing.

"It is surprising that females select mating partners without hearing the main song. The main song varies greatly among individuals and is thought to be important for selecting a mate in similar species," Soma said.

The study showed that female Java sparrows selected their partners for mating even without hearing the main song, according to UPI. Scientists concluded that the duet-dancing among sparrows could be their method of testing compatibility. They observed that both the male and female sparrows performed individual dances during the first meeting, but this did not result to a successful mating. A coordinated duet-dancing, however, resulted to a successful mating.

Java sparrows practice the art of courtship before mating. Generally, courting season for the sparrows occurs between January and July when the male birds claim a site for nesting. It then continues to chirp to attract a mate. There is actually competition among several male sparrows, each one trying its best to attract the female bird.