To be as sick as a parrot is to be very disappointed or unhappy. It is generally used by sports fans to express their disappointment about their team. ... It originated from the deadly viral parrot disease, which was passed on to humans and killed many people in Africa in 1973.

What's wrong with you if you are as sick as a parrot?

If you are as sick as a parrot, you are very annoyed or disappointed about something. In the 1970s in West Africa, there was an outbreak of the disease of psittacosis or parrot fever, which humans can catch from birds. ...

What does it mean to be as sick as a dog?

informal. : very sick.