Even if two birds don't get along, *most* birds still benefit from having a friend around.
My first two conures never got along, but I watched my first conure, Noel, copy the second conure, Charlie's behavior.
Noel passed on due to health issues and a few years later I took in a third conure, Jayde. Jayde and Charlie don't get along, but they do copy each other!
And none of these conures are the same species!
I once did an experiment with 5 adult, flighted budgies. My goal was to just get them comfortable enough to trust me and not be afraid of me. Well, it worked! A month after starting, I had all 5 birds flying out of their cage and to my hand to eat!
I had a cockatiel watching me... and she decided she wanted the same behavior. So I started feeding her by hand. Sunshine was a hand raised then ignored pet tiel and I was her second home.
A short while later, I took in Faye, another rehomed cockatiel. Faye has had at least 3 homes prior to mine, and probably wasn't well cared for in any of them. She watched my interaction with Sunshine so she wanted the same behavior, too! Except she wasn't confident, didn't trust me and always on high alert. Well, fast forward several months and she's eating out of my hands just fine!
As was the rest of the cockatiel flock, which consisted of my first tiel, Casey, who's extremely friendly, Pistachio and Kiwi, Sunshine's parents (Pistachio also being a *very* skittish cockatiel and wanted nothing to do with humans!) and Tomi Girl, another tiel that had at least 2 homes prior to mine and the last one nearly killed her from neglect.
Fast forward several years later, I no longer have a budgie flock, nor am I feeding the tiel flock by hand on a frequent basis. I found a pet only home for Sunshine, Kiwi unfortunately passed away, Pistachio is still going strong at 18+ years old and Casey pretty much remains Casey! Pistachio and Faye paired up as a couple. Tomi Girl really doesn't get along with the other tiels but she still considers them a part of her flock.
Well, there's been a few times that I decided to feed them by hand and Pistachio, the most skittish bird, is usually one of the first birds, if not the first one, to come over and eat from my hands! I currently have the cockatiels living with a wild caught african ringneck who does not like the tiels at all! She screams at them whenever they're in her way... Well, she was watching me feed the tiels by hand, so she got brave enough to venture over and eat from my hands, too! Only, since she doesn't like the cockatiels, she screamed at them, scaring them off, then she was 'alone', and being 'alone' near me freaks her out... so she'd scamper off away from me. She hasn't quite worked up the courage to eat from my hands!
Point being, birds do benefit from being around other birds, even if they don't get along! It's rare that a bird would do worse with another bird around.
As far as how accepting your tiel would be of another bird... well, that's entirely up to her!
it's very helpful. I think I'll start looking for another female cockatiel that needs a home
