budgies and cockatiels.

It depends on the size of the aviary and the particular birds involved. Budgies and tiels that have been raised together are likely to get a long very well. Some times, cockatiels and budgies do fine even introduced as adults. But, sometimes aggression can occur, and so you have to watch the flock very carefully for the first months. Bullying can happen: and although you would imagine this would be a large bird, a cockatiel is much more likely to be a target than an aggressor. Tiels are usually calm, quiet and affectionate in nature, and can be picked on even by a budgie who is half their weight and size.