What is a one-sentence summary of the following article?
Tail bobbing after exercise may be done while the bird is trying to catch its breath. However, if the bird is doing this behavior without having done any exercise, that can signal respiratory problems. If your bird is bobbing its tail without having done any exercise, have it seen by a veterinarian. Panting in birds can signal a variety of things, including that they are thirsty, that they have a respiratory infection, or that they just exercised. Make sure your bird has access to water immediately and monitor the panting. It it stops, then it was likely caused by physical exertion. If your bird likes to mimic sounds, panting can simply be a sound that they have heard that they are repeating. However, if your bird has had no way of hearing that sound, it is likely not a mimicked sound. Birds are generally sick for a week or two before they actually show signs of sickness. Birds tend to mask their sickness in the wild to avoid being spotted by predators and pet birds are nonetheless. Early diagnosis is the key to successful treatment. Rush your bird to an Avian Vet immediately.  Make sure you check your bird’s eating habits and food intake regularly. Reduced appetite is one of the first signs of a sick bird. Never ignore it if your bird shows signs of sickness. There is no time to procrastinate. Get your bird veterinary care immediately. If your bird is usually very vocal but has not been singing or chattering lately, then you should have it checked out by a veterinarian. A lack of singing or chattering can be a sign that your bird it not feeling well.

Summary:
Look for tail bobbing without previous exercise. Pay attention to panting. Notice changes in behavior. Pay attention to a lack of vocalization.