There were a lot things that happened socially among the humans and the parrots in Irene Pepperberg’s communication studies that were not presented in her scientific papers. Alex’s sexual orientation, for instance.
“[I]n general Alex preferred guys, especially tallish guys with longish hair, like Spencer [one of the graduate students who worked with the project]. Alex would often pad around the Tucson lab, looking for Spencer. When Spencer picked him up, Alex would run up his arm, perch on his shoulder, and perform the Grey’s mating dance. Spencer was the only person Alex called by name. He used to say, ‘Come here, Ser.’”
Among the mating behaviors of the African Grey Parrot is food sharing – or regurgitation. When besotted, Alex would barf on your shoulder – provided you were a tall hot dude with long hair.
“A favorite excursion was to a small lobby close to the lab. … Students passing on the staircase below the window were oblivious of Alex’s rapt attention to their comings and goings and to the cheerful whistles he produced for their benefit. He liked to wolf-whistle at boys who walked through the lobby, much to the consternation of the girl students tending him.”
source: Alex and Me: how a scientist and a parrot discovered a hidden world of animal intelligence – and formed a deep bond in the process by Irene M. Pepperberg