Abbasid Bowl with Man Playing Lute.
Museum of Islamic Art, Cairo.

A larger image of this Abbasid Bowl with Man Playing Lute. Museum of Islamic Art, Cairo.

Plate CXVII, La ceramique archaïque de l'Islam et ses origines by Pézard, Maurice (1920)

Referenced as figure 11, Fakes and forgeries in Islamic pottery by Oliver Watson (2004) (The images for Figs. 11 & 13 are transposed)
Fig. 11 - Detail of a dish, earthenware with lustre decoration over a white glaze, Iraq. 10^th century. Museum of Islamic Art, Cairo, showing restoration with foreign sherds and overpainting, transforming a bird into a sceptre.

Close examination reveals that the Cairo piece is heavily restored just at the place of the symbol, where a mishmash of foreign sherds and over-painting exist (fig. 11)
...
The mysterious symbol is explained by comparison with other dishes - notably a piece in the Metropolitan Museum of Art - it is the tail of a bird.³¹
Source: p. 524, Fakes and forgeries in Islamic pottery by Oliver Watson (2004)