The Biertan "Ushak Bird" rug, Ushak-Selendi area, late 16th century, 149x214cm. The Biertan Evangelical fortified church (inv 63), Romania.

The weavers of the so-called Bird rugs might well have believed that they were creating a pattern of stylised birds, but the original motif probably represented something quite different. Most of the large Bird carpets - of which at least 22 examples are known - have the cloudband border, as seen here, nine or more have a border composed of offset half-diamond medallions, one has the so-called 'Gothic' border and one a cartouche border. The largest, formerly in the Piyale Pasa Mosque, Kasimpasa, Istanbul, and now in the Museum of Turkish and Islamic Arts, is 523 cm long; while Bird carpets are rare in Turkey, the presence of the Piyale Pasa example demonstrates that they were not all made for export. The Biertan, only a section of which remains, is the sole surviving large Bird carpet in Transylvania. The first depiction of a Bird rug in a European painting is in Hans Mielich's Portrait of Count Ladislaus von Hag (?), circa 1548, in the Kress Collection. It is likely that Bird rugs were made from at least the first half of the 16th century, as several are mentioned in European inventories from this time.

http://www.transylvanianrugs.com

illustrated in Stefano Ionescu, Antique Ottoman Rugs in Transylvania