The sooner the eggs are laid, the better the birds sing

Birds hatching from the first eggs in a litter always have longer and more complex tunes than the kids.

In most birds, males use songs to seduce females. Many studies show that the songs of healthy males are often loud and complex. In addition, their singing time is long.

Masayo Soma, biological language specialist at the Riken Brain Science Institute in Wako, Japan, and his colleagues wanted to find out if the bird's birth order in a batch of eggs affects its voice. is not.

"I think the time of birth of a bird in a litter affects their singing ability, because the pre-hatched animals always have more food, so they rarely suffer from stressful situations. more than you, " Masayo said.

A flock of Bengal sparrow.Photo: petngarden.com.

To test the hypothesis, Masayo and his colleagues collected many groups of Bengale finches. They put all the first eggs in each nest into one group and repeated it with the next eggs. The scientists gave 9 pairs of finches to hatch 16 eggs, each containing 4 fruits. All young birds are numbered sequentially in their nest. After the eggs have hatched, they put 9 males into the cage for them to sing to the young birds.

When young birds reach adulthood, the team recorded their songs. The results showed that the hatching order of the eggs did not affect the song.

However, the order in which an egg is laid affects the complexity of the bird's melody. Those hatched from premature eggs tend to pick up more complex melodies than others.

Scientists give different explanations about this phenomenon. According to Masayo, the higher the androgen content (hormones that are involved in the development of males), the greater the probability of young birds singing or higher. The amount of hormones in the eggs may decrease gradually according to their order of birth. Therefore, eggs that are born early always have more androgen.

Masayo will add androgen and many other substances to the sparrow's eggs to find out if they affect the quality of the bird's voice.