Can you house cockatiels of the same sex together, such as two male cockatiels or two female cockatiels, without them fighting? Generally speaking, cockatiels get along fairly well with each other, and keeping ‘tiels of the same gender will work out without serious problems. (Keeping cockatiels of different sexes together will just result in a bunch of baby cockatiels that need homes.)
Years ago, I had a friend who had two very delightful male cockatiels. They were from the same clutch so they were the same age and had been raised together. The cockatiels had separate cages and both received attention together and separately. They played very well together and would bicker occasionally, especially about who was getting more attention from their caregiver. It was fun to watch the ‘tiels bicker because they would squawk and run around each other, but were never physically aggressive.
I have also known people who have had multiple cockatiels. One woman had seven ‘tiels that were all related to each other. She had the parents and kept their first clutch. The cockatiels had cages but the living room was set up as a giant play room for them, and all the ‘tiels explored the entire room on a daily basis. Sitting in her living room with the cockatiels out felt like being in a scene from "Gulliver’s Travels.” At first everyone got along, but as the baby ‘tiels got older, one of the young males tried to displace his father as the dominant cockatiel. Eventually, she separated them by gender when she let them out.
Because ‘tiels are such social birds, I think there are many situations when cockatiels can be kept in multiples and get along. They key is for people to pay attention and manage their behavior so that they stay tame to them and the other cockatiels. Another key ingredient is giving the cockatiels plenty of space so if some of them do start fighting, they have a place to escape to. Some male cockatiels will fight if kept in the same cage together or put in a travel cage together and they could end up hurt.
Excerpt from the Popular Birds Series magabook Cockatiels with permission from its publisher, BowTie magazines, a division of BowTie Inc. Purchase Cockatiels here.