The primer pair sex1/sex2, which can be widely applied for sex identification in Galliform species, was used to determine the sex of 17 Passeriform species. As CHD-W
fragments tended to be preferentially amplified, which may cause unnecessary misidentification in bird species with little difference between CHD-Z
, we modified sex1 and sex2, obtaining sex1' and sex-mix respectively. Primer sets were then recombined to conduct sex identification. After testing several Passeriforme birds of known sex, we found that the primer pair sex1'/sex2 was better at limiting the preferential amplification of CHD-W
fragments. As they are being frequently used in sex allocation study of Aegithalos concinnus
and song learning research of Lonchura striata
, we can expect more applications of this primer pair to further studies in Passeriformes.