Range size and distribution of species can be greatly influenced by a wide range of ecological, behavioral, and historical process such as competitive interactions between two species in hybrid zone. Black-headed (Emberiza melanocephala) and Red-headed (Emberiza bruniceps) buntings known to hybridize southeast of Caspian Sea. Since spatial distribution of parental species is an important factor to determination of opportunities for hybridization, breeding range distribution of Red-headed Bunting was revisited along the exhaustive field works during Aprill-September 2012 and 2013 in north and northeastern Iran. Results showed that breeding distribution range of the species has been expanded westward over 170 km in north of Iran. This is noticeable expansion during the past four decades. The easternmost distribution range of the species has been reported from Shahrud in Semnan province and Behshahr in Golestan province. The new westwards records of the species is reported from Damghan, Semnan, Garmsar and northeast Tehran, highlands of Neka and Nushahr for the first time. The reasons for the recent westward expansion of the species across its range are still unknown. It seems spread of agriculture areas and deforesting of previously continuous Caspian forest to be among the main reasons attributed to recent expansion range of the species. Range expansion may be also associated to climate variables or competitive superiority of Red-headed Bunting in the contact zone

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