Birds 913 Beron P. (ed.). Biodiversity of Bulgaria. 3. Biodiversity of Western Rhodopes (Bulgaria and Greece) I. Pensoft & Nat. Mus. Natur. Hist., Sofia Birds of the Western Rhodopes (Bulgaria and Greece) TSENO PETROV, DIMITAR DEMERDZHIEV, GEORGI POPGEORGIEV, LYUBOMIR PROFIROV, KALIN VELEV, KAMELIA DIMITROVA, DIMITAR PLACHIYSKI Petrov T., D. Demerdzhiev, G. Popgeorgiev, L. Profirov, K. Velev, K. Dimitrova, D. Plachiyski. 2006. Birds of the Western Rhodopes. - In: Beron P., (ed.) Biodiversity of Bulgaria. 3. Biodiversity of Western Rhodopes (Bulgaria and Greece) I. Pensoft & Nat. Mus. Natur. Hist., Sofia, 913-948. Abstract. The article represents the result of a study of 247 bird species occurring in the Western Rhodopes (Bulgarian and Greek parts – a total of approximately 10 000 km 2 ).Two hundred and fourteen (86.6%) bird species are established in both parts of the mountain, 22 species (8.9%) are found only in the Bulgarian part and 11 species (4.5%) only in the Greek part. The breeding species (residents and summer visitors) are 162 (65.6%). Migrant species are 23.2% out of the total number of species: 5.2%-winter visitors, 4.4%-vagrants and 1.6% (4 species) are extinct. Data on species number and distribution in the Western Rhodopes is included. Seven of the established species are listed in the Global IUCN Red List, 18 - in the European IUCN Red List, 74 are declining, 7 are rare. Information on six sites recognized as Important Bird Areas and potential Natura 2000 sites is given. Key words: Aves, Birds, Western Rhodopes, Bulgaria, Greece, distribution, conservation. Introduction The birds of the Western Rhodopes have not been subject to complete study. The region is extremely interesting regarding the bird fauna and considering the fact it is the northernmost or the southernmost part of the area of some species (Lanner, Capercaillie, etc.) in Europe. In addition to this, the Western Rhodopes extend on the territory of both Bulgaria and Greece and the geographical boundaries of both countries have been strictly guarded for many years hence the ornithologists’ presence in the area was restricted. It imposes the necessity of prompt actions for the study and conservation of the avifauna in the region as well as designation of integrated protected territories on both sides of the boundaries. The aim of the current paper is to make an inventory of the birds in the Western Rhodopes, including: complete bibliography, reviewed data on separate species,