A cockatiel sleeping with feathers fluffed can be normal behavior or sign of illness. If your cockatiel's feathers are fluffed when he's sleeping, observe the bird closely and be prepared to make a vet visit. Sick birds can hide their illnesses until it is too late for treatment.
Normal Cockatiel Sleep Patterns
Nighttime is when a cockatiel gets the majority of her sleep. She will “roost,” which means retreating to a high perch where she feels safe and comfortable. At night, a cockatiel’s body temperature is lower, so she may do several things to conserve body heat. She may stand on one leg, tucking the other up under her warm belly. She may tuck her head under her wing or she may fluff up her feathers to trap warm air next to her body. Keeping at least three sides of the cage covered at all times helps keep temperatures constant and your cockatiel comfortable.
Feather Fluffing as a Sign of Illness
A cockatiel that seems unusually sleepy during the day may be getting sick. She should be active in daylight; feeding, preening, exploring, exercising and calling out. She is curious about what is going on around her and eager to interact and play. If she is sleeping more than the occasional nap, and especially if she is fluffed up, she might not be feeling well. Sick birds often huddle at the bottom of the cage, fluffed up and looking sleepy. They can quickly become too weak to stand on a perch or eat. A cockatiel behaving this way needs evaluation as quickly as possible by an avian veterinarian.
Other Reasons for Feather Fluffing
Feathers are an extremely important part of a cockatiel’s body, and they require lots of attention from her. She will fluff up her feathers as part of “preening,” which means to clean and rearrange her feathers. Fluffing the feathers allows dirt and other debris to fall out as she cleans each one. A cockatiel will also fluff up her feathers and then shake her whole body as a way of relieving bodily tension -- think of a human stretching. A nervous or frightened cockatiel may fluff her feathers as a defensive measure, trying to appear larger than she is. A notable change in temperature may cause a bird to fluff up because she is chilly. Warming her environment a little should return a healthy bird to her unfluffed normal stature.
The Special Cockatiel Feathers
Cockatiels have special feathers on their heads that sometimes appear to be fluffing up. These feathers are called crest feathers; cockatiels use them for communication. Calm cockatiels will usually have their crest down against the top of their heads. But start talking to her, playing with her or showing her food and her crest may stand straight up. This means she is alert, excited and interested. A frightened cockatiel may flatten her crest tightly against her head and may even hiss. A peacefully sleeping cockatiel will never have her crest up, even if her other feathers are fluffed for warmth.
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