Bird images in the mosaics of Late Antique basilicas in the town of Sandanski (Blagoevgrad Region, SW Bulgaria)

This paper presents and analyses for the first time all data on bird images of two Late Antique basilicas of the Romаn period (5th–6th c. AD) in the town of Sandanski (SW Bulgaria). A total of eight species have been recognised on the floor mosaics of both basilicas: Anas platyrhynchos, Bucephala clangula, Dendrocygna viduata, Nettapus coromandelianus, Marmaronetta angustirostris, Porphyrio porphyrio, Psittacula krameri, and Sypheotides indicus. Exotic birds of Palaeotropic (Ethiopian) and Indomalayan (Oriental) distribution confirm once again the active ancient Roman contacts with East and Trans-Saharan Africa and the Hindustan Peninsula.


Introduction
The town of Sandanski is located in the Petrich-Sandanski kettle and was inhabited from about 2200 BC. Its ancient built area was situated within the present territory of the town. Its height in the Antiquity was in 4 th -6 th century AD when it was an important Christian centre (Petkov, 2006). Ancient mosaics of both studied monuments decorated two important Christian temples -the Bishop's Basilica (in the Early Christianity Complex, uncovered in 1967), evaluated as the most valuable building in the town (middle of 4 th -middle of 6 th century) and measured as 22 | 36 m. Its floor mosaics were created in the "Opus tessellatum" and "Opus sektile" style. During that period Sandanski was a main economic and cultural centre in the region. It played an important role in the dissemination of the Christianity.
The second monument, the Basilica of Bishop John, is now located at the area of the present Archaeological Museum of the town of Sandanski (AMS). Its mosaics mostly represent images of fishes and birds and are dated also at 5 th -6 th century (Petkov, 2006). The presence of both basilicas was unsuspected until 1917, when the first archaeological finds were excavated during building operations.
Bird images appear in many archaeological monuments excavated throughout the country. The great majority of them remain still unexamined by ornithologists. The most comprehensive study on the place of birds in the everyday life and the art of people in the Thracian and Roman periods was published quite recently (Boev, 2018). It does not deal with the bird mosaics of Sandanski. That is why they are the subject of the present study.

Material and methods
On 1 June 2018 we visited both monuments in Sandanski and photographed all bird images of the exposed mosaics. The present paper covers only mosaics exposed to the visitors. A small part is still under restoration (Dr Anton Kovachev, director of Archaeological Museum of the town of Sandanski). In our identifications we considered colour features, poses and all general proportions of the body parts of the birds.
At present, only three species (Anas platyrhynchos, Bucephala clangula and Marmaronetta angustirostris) are part of the recent avifauna of Bulgaria (Ivanov et al., 2009(Ivanov et al., , 2015. Psittacula krameri is con-sidered as potentially invasive species and has penetrated in Bulgaria even over the last two decades (Grozdanov et al., 2017). Anas platyrhynchos and M. angustirostris are recorded in Bulgaria, the first species as a common breeder, the second as an extremely rare bird with unknown status (Nankinov et al., 1997). The mallard's distribution (Fig. 11) covers most of Europe, Asia and North America, and reaches even Tasmania and New Zealand (Carboneras, 1992). Marmaronetta angustirostris has sporadic Palaearctic distribution (Fig. 12), from Spain and North Africa through the Middle East and South-west Asia and China. The species is dispersive and partially migra-      tory (Carboneras, 1992). Bucephala clangula is widely spread anatid with Holarctic distribution (Fig. 13). At present, the species breeds out of the regions of the former Roman Empire, but some populations winter in the Mediterranean (Carboneras, 1992). Dendrocygna viduata is a resident widely spread duck in the Paleotropic and Neotropic regions (Fig.  14). It inhabits all Sub-Saharan Africa (Carboneras, 1992).
Nettapus coromandelianus is widely spread in Hindustan and Indochina (Fig. 15) but the Northern East-Asian populations make long-distance south migrations and winter in East Australia (Carboneras, 1992). Sypheotides indicus is mainly a resident species. It breeds and winters mainly in the Hindustan Peninsula (Fig. 16). In summer rarely reaches Nepal (Collar, 1996). Porphyrio porphyrio is a resident species spread from SW Europe (Fig. 17) to Australia, South Africa and New Zealand (Taylor, 1992). Its mosaic images are known in many Bulgarian Roman towns, villas, etc. (Boev, 2018). Psittacula krameri is spread in the Sub-Saharan Africa, north of the equator, in the Near East and Hindustan (Fig. 18). Elsewhere it is a resident species (Collar, 1997). The images of these parrots are also present in the Bishop basilica in the ancient Philipopolis (Boev, 2018).
The Roman-Hindustan contacts and trade are well known (Smith, 1908, Miller & Innes, 1969. Moreover, the trade of exotic animals of other continents was indicative for the wealth of their owners. Many Roman (i.e. European!) owners of villas decorated their floors with picturesque mosaics of animals from Africa, India, even Indonesia.
The hunting or decorative animals are represented in such detail that it is possible to identify the species. In some Roman villas in Italy Indian rhinoceroses, Indian elephants, Indian peafowl and tigers can be seen. All these (and many other) animals were transported to Europe in cages by ship.

Conclusions
Although, no ornithoarchaeological evidences have been obtained so far in Bulgaria for the confirmation of the former presence of individuals of these exotic Afrotropical and Indomalayan birds, their high informative mosaic images in the Bulgarian ancient monuments support the importation of these birds as live specimens in the ancient Bulgarian lands during the Roman period. They also elucidate the importation of decorative exotic birds by the Romans along with the large animals as ostriches, Indian rhinoceroses, big felids (lions, leopards and tigers), etc. On the other hand, we know that "the images on floor mosaics in early Christian temples throughout the Eastern Mediterranean and the Balkan Peninsula, in particular, are symbolically loaded and standardised, strictly subject to liturgical requirements. Styling analyses of numerous monuments from this period clearly demonstrate the existence of common templates and patterns used by mosaic masters in different parts of the ancient world" (Dr Veselka Katsarova, National Archaeological Institute and Museum, pers. comm.). Having in mind the scope of the Roman Empire, we cannot exclude any of these two possibilities.