Have a complete medical check-up performed on the new bird as soon as possible by an Avian Certified Veterinarian. During the initial medical exam, give the vet all of the background information that you have on the bird. Some signs of stress are loose watery droppings, shivering, heavy breathing, fluffed feathers, lack of vocalizations, poor appetite, and lethargy. These symptoms should disappear in a few days. Building a trusting relationship may take longer with an older bird.
Older birds can form strong bonds with their owners if given the time to trust their new owners.
Proceed slowly, while always keeping the bird's comfort level in mind. Approach the cage slowly, hand at your side or behind your back, and speak softly. Sitting on the floor will help the bird to feel less threatened. Allow the bird to determine how fast the relationship will develop. Don't force your bird into interacting with you.