Yes, cockatiels can easily get lonely. Cockatiels are highly social birds that live in flock structures in the wild. When kept alone without any avian interaction, a cockatiel can exhibit signs of loneliness. As animals that naturally spend their days engaged with other cockatiels through behaviors like preening and play, isolation from their own species can be stressful. A lonely cockatiel may cry excessively, become lethargic, or pluck its feathers. While bonding closely with human owners provides some stimulation and companionship, it does not replace the complex social behaviors cockatiels display towards each other. Keeping a pair of cockatiels or housing more in a small, well-introduced flock ensures each bird has constant company when their human is away. This prevents cockatiels from feeling lonely by fulfilling their innate need to interact with and engage their own kind.