London, Oct 25 : Scientists at the Riken Brain Science Institute, in Wako, Japan, have found that birds that come from the earlier eggs in a brood are more likely to be better singers.
Most male birds use songs to show their fitness to potential mates, and previous studies have demonstrated that the healthiest males tend to sing the longest, loudest and most complex songs.
Masayo Soma and her colleagues from the Riken Brain Science Institute wanted to find out if the order in which birds hatch affects their song.
"I expected to detect age hierarchy in song, because older siblings are stressed less and obtain more resources growing up," Nature quoted Soma, as saying.