parrots - One unique feature of all pionus is a wheezing hissing sound they sometimes make when they are frightened. Your first response might be to assume they are sick, as it sounds similar to an asthma attack. However, if you back off the sound should stop. They can also make a variation of this sound when being petted. Usually in this case it is a much softer sound, closer to hissing. The other thing to be aware of is when you bring your pet to a vet or bird groomer. If they are not familiar with pionus they might think the beak is overgrown. It does look overgrown when compared to the beaks of some of the more common parrots. Make sure you look at enough pictures so that you know what is right for your bird. Remember that the fully adult bird will have a longer upper mandible than a baby.