The purple coot is more properly known now as a purple swamphen
Aelian De Natura Animalium 5. 28
“The purple coot, as well as being very jealous, possesses this oddity as well. For people say that it cherishes its family and delights in a shared life with its companions. I heard that a rooster and a coot were raised together in the same house—they ate the same things, and they measured out the same steps, and got dirty in the same place. From these experiences, an amazing friendship developed between them.
Then, when there was a festival, the lord of the house sacrificed the rooster and included it in a banquet for the household. The purple coot, now without his companion and intolerant of the solitude, killed itself through starvation.”
Ἴδιον δὲ ἄρα <ὁ>πορφυρίων πρὸς τῷ ζηλοτυπώτατος εἶναι καὶ ἐκεῖνο δήπου κέκτηται. φιλοίκειον αὐτὸν εἶναί φασιν καὶ τὴν συντροφίαν τῶν συννόμων ἀγαπᾶν. ἐν οἰκίᾳ γοῦν τρέφεσθαι πορφυρίωνα καὶ ἀλεκτρυόνα ἤκουσα, καὶ σιτεῖσθαι μὲν τὰ αὐτά, βαδίζειν δὲ τὰς ἴσας βαδίσεις καὶ κοινῇ κονίεσθαι. οὐκοῦν ἐκ τούτων φιλίαν τινὰ θαυμαστὴν αὐτοῖς ἐγγενέσθαι. καί ποτε ἑορτῆς ἐπιστάσης ὁ δεσπότης ἀμφοῖν τὸν ἀλεκτρυόνα καταθύσας εἱστιάθη σὺν τοῖς οἰκείοις· ὁ δὲ πορφυρίων τὸν σύννομον οὐκ ἔχων καὶ τὴν ἐρημίαν μὴ φέρων ἑαυτὸν ἀτροφίᾳ διέφθειρεν.