Study of sexual dimorphism and morphological variations of Red-headed bunting (Emberiza bruniceps) within its hybrid zone with Black- headed bunting (Emberiza melanocephala) in the Iranian Plateau

Introgression among hybridizing species plays an important role in intraspecific variations and acquisition of novel traits especially along hybrid zones. The breeding ranges of the Red-headed and Black-headed buntings (Passeriformes) overlap in southestern Caspian Sea where hybrid specimens can be found. Mainly using Mist nets، we sampled 81 specimens of the Red-headed bunting (57 males and 24 females) from north and northeastern Iran in order to investigate sexual dimorphism، intraspecific variation، and role of hybridization on species-specific traits. The Independent sample t test and the PCA were performed on 15 morphometric characters using SPSS and PAST softwares. Furthermore nine chromatic characters were coded and analyzed in PHYLIP and PAUP softwares. Results of morphometric characters showed significant difference between male and females. Analyses of plumage coloration showed that there are at least four morphotypes in the Red-headed bunting. We concluded that using morphometrical and especially chromatic characters we will be able to discriminate pure individuals from most F1 hybrids.