This is a common parrot behavior associated with aggression and/or excessive noise correlating to the pet bird’s favorite person engaged in talking on the phone.
At the risk of being anthropomorphic, the probable cause is jealousy. After all, the phone rings and the person immediately answers it, puts it on his/her shoulder and gives it 100 percent of his/her attention, therefore completely ignoring the bird.
Do not answer the phone while interacting with a pet parrot. Instead, put the bird down and move away first. According to Mattie Sue Athan, facing the bird and talking into the phone as if the person is talking to the bird will block a lot of noisiness, as doing this might prevent the bird from feeling ignored.
Disclaimer: BirdChannel.com’s Bird Behavior Index is intended for educational purposes only. It is not meant to replace the expertise and experience of a professional veterinarian. Do not use the information presented here to make decisions about your bird’s health if you suspect your pet is sick. If your pet is showing signs of illness or you notice changes in your bird’s behavior, take your pet to the nearest veterinarian or an emergency pet clinic as soon as possible.