Passage 6.26.3
ἐν ἀκροπόλει δὲ τῇ Ἠλείων ἐστὶν ἱερὸν Ἀθηνᾶς· ἐλέφαντος δὲ τὸ ἄγαλμα καὶ χρυσοῦ. εἶναι μὲν δὴ Φειδίου φασὶν αὐτήν, πεποίηται δὲ ἀλεκτρυὼν ἐπὶ τῷ κράνει, ὅτι οὗτοι προχειρότατα ἔχουσιν ἐς μάχας οἱ ἀλεκτρυόνες· δύναιτο δʼ ἂν καὶ Ἀθηνᾶς τῆς Ἐργάνης ἱερὸς ὁ ὄρνις νομίζεσθαι.
On the acropolis of the Eleians there is a temple of Athena; the statue is made of ivory and gold. They say the statue itself is the work of Pheidias, and a cock is represented upon the helmet, since these birds are extremely eager to fight. But it is also possible that the bird is regarded as sacred to Athena Ergane.