Some signs of stress in birds include feather plucking, loss of appetite, excessive vocalization, aggression, and repetitive movements. To alleviate stress in birds, you can provide them with a comfortable and spacious living environment, regular social interaction and playtime, a balanced diet, and opportunities for mental stimulation. It's also important to ensure they have access to fresh water and proper rest. If you notice signs of stress in your bird, it's best to consult with an avian veterinarian for further guidance and support.