Common signs of stress in birds include feather plucking, loss of appetite, anxious behavior such as pacing or restlessness, excessive vocalization, and aggressive behavior towards other birds or humans. Additionally, changes in the bird's droppings, such as increased frequency or unusual colors, can also be an indicator of stress. It is important to monitor your bird's behavior and physical condition closely, and seek advice from a veterinarian if you suspect your bird is experiencing stress. Creating a peaceful and enriching environment, providing proper nutrition, and ensuring regular social interaction and mental stimulation can all help alleviate stress in birds.